Alright, bear with me here.
Stuck in this prison for what seems forever,
How long do I have left? 10 years? 20 years? Never?
Sometimes, you are stuck in the bathroom for a while. Because... you know.. reasons.
Over the years, you've stuck to this same ritual.
Only, instead of purpose, it's mostly habitual.
Many people go to the bathroom at the same times every single day, if only because it fits their schedule, not that they really need it.
Look to where you rest to find what I am.
Sometimes, the bathroom is the only place you can catch a break and be all alone. In other words, it is great for being truly at rest.
I would dare say that the toilet's view of you is not terribly flattering
Spells "SHOOL", but from comments I imagine it was meant to say "School". Students go to the bathroom to get out of class daily.
Seems like a long shot to me, but what the hell, let's go for it.