TIFU - Destroyed my roommates Tater-Tot Casserole.. (info inside)

My roommate prepared a Tater-Tot Casserole for us for dinner, our first nice dinner since moving in (we are both out of money and she had a little and bought ingredients for it) she went to a movie with a friend while I stayed at home to take the Casserole out of the oven.

The casserole finished, I took it out and ate my share and thought it would be nice to put it back in the oven to keep it warm for when she got home. However, I forgot to turn the oven off.

2 hours later I went to see if it was still warm, found it as a burning crisp in the oven.

I feel sick, shes going to be home in a few minutes. :(