To be a bit upset about this at a toddler session?

I think you've found the real crux of your disquiet, that you value the group more than you feel valued by them or the leader. There's a fondness to groups when you have a preschool child as its part of their little life growing up and is quite precious. I have a 2.5 years old so go to lots of groups like that so I know how it is.

The leader obviously sees her relationship with thr attendees as friendly but cordial as this is a business to her, I don't know the structure of the setting but are the last 15 minutes quite structured where she's delivering something like storyline that makes it hard to stop doing to address an absent parent?

The other angle is, because she's known you for so long, she assumed you had chose to pop out for a moment and was comfortable keeping half an eye on your child. I guess she may have thought it was deliberate and didn't want to bring it up, maybe a toilet emergency tbh and so just avoided drawing attention to it.

The lesson here is to simply take control and say something at the time to avoid speculation and spiralling, clear up any potential miscommunication etc.

Oh, dear, what can the matter be?

So music was playing, so this adds to why no one heard you knock and why you should have mentioned it to the leader at the end!
A quick, I don't know if you are aware but I was locked out of the room for 15 mins because of the way the door works. As we do lots of noisy activities/have music can you look at ensuring people have access to come back in if they leave.

If it was that obvious you were leaving then it goes back to they thought you needed longer in the toilet (upset stomach, period, or even making a phone call without your child present). They may have thought as you didn't say anything to anyone you clearly aren't bothered about leaving your child.

@CremeEggsForBreakfast I agree - the onus was on the person leading the session to give a health and safety briefing, which would have covered what to do if you need to leave the room and how to get back in, but clearly she did not.

Depends on what you mean by "leaving the room ".
I go to a a couple of traditional toddler group/stay and play where the toys are spread through multiple rooms. Yes, I let my child roam and I might have a natter with another parent while he wanders into another space.

In the OP's scenario I might have whispered to the parent next to me that I was just nipping for a tissue but it sounds like the bathroom was as close to the class as my kitchen is to my living room so I also might not have done, figuring that I'd be very quick and the teacher would notice a parent leaving the room (given the class is a structured thing so it's not an unpredictable and busy environment like a stay and play).

The teacher really should have mentioned the coded doors. Even if OP had taken her DD with her, she'd still have missed a significant amount of the class that she'd paid for.

Oh FFS. That's next level bonkers. And why oh why would anyone waste litres of water flushing a toilet instead of putting a tissue in the bin?

I’m afraid I also can’t fathom just walking out and not saying anything to anyone, leaving your child when you know even 15 mins without you will have her so upset she’s clingy for the rest of the day and distressed as you say.

it was just one of these things, you didn’t realise the door was locked behind you the leader didn’t realise why you’d gone, they didn’t know if you went to the loo or to take a call, they didn’t know if you had bad guts and were stuck in the loo.

nexg time tell someone, don’t just walk away from your kid.

& I read that the room was next door, so close etc etc - whatever, your child should not have been left while you went out of the room without discussion.

I can’t imagine leaving my two year old in the room without saying to someone - i’m popping out can you watch her or taking her with you. It’s not stay and play, your child, your responsibility. I can’t get past that - the rest, ie your reaction, I think is dramatic given this is on you.

How strange. What sort of venue was it? Were you made aware of evacuation procedures in case of emergency? Were you completely trapped?
How many children were at the venue and what was the ratio of adult to child?
I would be raising this with those who run the venue if I was you.

I think if all the parents weren't informed at the beginning of the session about the situation with the toilets and the need to know a code to get back into the room then the group leader was very remiss. I think OP has every right to be upset annoyed.

What i realky dont understand is why she didn't raise the issue before she left..

I think that OP shoukd get in touch with the leader or whoever is responsible for the administration of the group before the next session and let them know how she feels. Especially as it is going to impact on how she feels about attending the group in future.

The leader should have explained the door situation ahead of time. I understand if it was a music or otherwise loud session that knocking on the door wouldn't be heard. I would be upset if that happened to me too, I can understand feeling unable to raise it with the leader at the time and just wanting to leave but I would message after the session and let them know what had happened.

I think posters are being a bit unfair here. I can definitely see how this happened and 15 minutes is a really long time. Definitely worth feeding back to the person running the group. They presumably just need to print and laminate a document with the codes on it and then make it available to parents so it's a reasonably easy fix.

She probably thought you had toilet issues, she’s not going to come over and ask if you’re okay, she wouldn’t want to highlight it and embarrass you.
I don’t really get why you expect her to thank you for coming to the class? I go to baby sensory every week and I always thank the leader for running a lovely session, i don’t expect her to thank me. Did you thank her?
I get that this situation was frustrating and annoying for you, but I think not wanting to go back next week is a bit daft.

But you still haven't acknowledged you could have told someone you were nipping out. Regardless of how close the toilet is to the room you were still leaving your child, however briefly, out of your eye sight. A quick, I'm just getting some tissues, would have meant someone would know you were out of the room (though maybe they would also just assume you needed longer in the bathroom and saying you needed tissues might have been a cover for something else).

I think it is up to the group leader to explain in advance that the toilets are behind a locked door that you won’t be able to get back in from. Especially as it is a new venue to you. There should be a note on that door to say.

I would be unhappy if this happened to me and I would complain to the group leader (or activity owner if there is one) and to the building owners.

Separating a mum from a two-year old for 15 minutes is unacceptable.

If others were leaving, she had probably done her big, "Thank you all for coming" type thing at the end. You probably just missed it. She wouldn't repeat it for everyone individually unless someone came directly up to her to speak, surely.

OP, it’s ridiculous not to have raised it with her at the end of the session, especially if it’s a new venue — she needs to flag it up to all parents attending all classes at this venue. ‘She didn’t look like she wanted feedback’ is juvenile and passive-aggressive because it made you feel ‘unimportant’.

No, obviously it shouldn’t have happened, and absolutely understandable you felt panicked, but for god’s sake flag it with the teacher, rather than being silently upset and angry.

But would you leave your child in the room whilst you left the room, without telling anyone?

With hindsight it would have been better to bring her child but obviously she didn’t think the door would lock and so she’d be gone less than a minute.

There was a thread the other day about how relaxed other countries are compared to here. I think this is an example of it.

you could have been in the loo for that time though?

I think you've had some unsympathetic responses here OP - if that had happened to me, I'd have been left quite shaken up. Being locked out of a place, with your child inside, would naturally give rise to feelings of panic. 15mins would feel like a long time in this situation.

Plus nobody heard you knocking - is the group really noisy? It's an issue if people can't get to a loo without being locked out of the room - and this does need raising with the group leader.

If an internal door is on a magalock, it automatically releases when a fire alarm goes off.
OP, I’m confused here. Why did you leave your DD in the room when you left the room? You did so because it was quicker, and was safe to leave her with other people presumably. I’m also stunned that after 15 minutes of banging on a door to a room full of people no one heard you.