Ticket to pass
The simple fact is that if you do not have a valid ticket you are breaking the law. She was not able to produce a I.D and is there fore able to be prosecuted. She will be held in custody until she is able to prove her identity.
She was in a hurry and none of us would like to be fined or be put into custody because of being in a hurry. But on the other hand she is still taking up space where other people may have payed for, but cannot access because of her.
Ultimately she was in the wrong and was not able to produce her identity, and therefore the ticket inspectors had every right to place her into custody. she will miss her final exams, but it was her responsibility to purchase a ticket and have her I.D