I do still think that the biggest problem here is a 10yo who is not confident enough to be in a house, at teatime, for a short period, apparently shaking too much to use a phone.. I honestly find that very very hard to believe.
At 10 years of age I was capable of staying in while my mum went to the shops, and capable of going to the shops for her too.
I also knew which houses I should go to if there was an emergency.
If this was a 7 or 8 years old, I could have more understanding.
We also didnt even have a house phone, and didnt have one until I was 16, got my first job, and paid to have one put in myself!
I also find it hard to see how a five minute drive can take 45 minutes to walk either, unless it is on a motorway.
because the journey home from ASC is 45 mins walk, although only 5 mins by car, so it was over an hour.
I assume from looking back at this, you were walking, not driving, or you would have got there much quicker.. and am also wondering why you didnt ring the house to see if she was there? Would that not have been a logical assumption, given that the worker who normally gives her a lift was not there, you would think "oh, xxx must have taken her home early perhaps".
You could have rung the house, spoken to your daughter and said "be there soon".