Waking up in a coffin wasn't what you would a lovely morning surprise. Neither was getting set on fire by a demon cat. Or being told you had been mistakenly transported to another world. But hey, since life is giving you lemons, might as well squeeze them into the eyes of that Headmaster so he'll get you home quicker.
(Or, my purely self-indulgent excuse to put all my crazy head canons into action. Reader-insert story).