She must have worked herself into an 'error loop'. She must have been working out when the right time was to leave the toilet and never quite felt it was the right time. Her boyfriend giving her food in the bog is not just disgusting but was fuelling her delay for sure.
As time went on it must have compounded and she became more and more unsure of when the right time to leave the toilet was.
You would need to be slightly cookoo to get yourself into that fix in the first place, then you would probably need to suffer some emotional stress to make it last so long. A stupid boyfriend for giving her food in the toilet and never calling for help should be flogged with a fish in public!