Before school: 'Miss! Miss! Miss!', phones ringing, parents wanting to sort out that Jimmy looked at Andrew funny and it's a symptom of inadequate safeguarding and a concerted campaign of harassment and what are YOU going to do about it RIGHT NOW, calls that Freddie isn't going to be in school today because his arm aches from having to write for two twenty minute tests and has to be supervised to take paracetamol, other staff wanting you to confirm that yes, you've received the email, yes, you've emailed such and such already and yes, it cannot be sorted out any other way. Attempt to nip to the loo, there are three people waiting outside, have to give it a miss until break.
Breaktime: 'Miss! Miss! Miss!'. Two people waiting outside the loo and one in there with stomach issues, it's 3 minutes until the start of lessons and you're needed the other side of the site to 'greet students as they walk in'.
Lunchtime: Lunch Duty, clubs, 'Miss! Miss! Miss!'. Caught by a playground dispute which takes until 1 minute before the bell rings.
After School: 'Miss! Miss! Miss!', detentions, parents phoning because you haven't replied to the email they sent five minutes previously and whilst you're here, can we discuss James' future admission to the Royal College of Music and can you do anything about the wicked music tutor who told him off for attempting to insert a ukulele that he cannot play for love nor money into Adam's orifices, then Adam's parents phoning because somebody attempted to shove a ukulele up an orifice and 'Miss! Miss! Miss!' and an email from SLT saying 'No hurry, but I want this done in the next 8 minutes'... Queue for the toilet is five deep and if you stay any longer, that Assistant Head outside will be in here, spot you and will 'just need to discuss the comments in your reply for a minute. And it's not right to dash off, as SLT are here until 9.30pm each night, you know. And we're here by 6am, you know.'
That kind of thing.
In any case, no member of staff has ever pissed themselves even on the busiest days, so I'm pretty sure that 4 hrs between pees is enough time when there are no other medical issues that would have been mentioned in a post about using a disabled toilet for convenience.