It really is one of those mornings!
Mrs Kringle reasons that the scream can't be coming from the gym, and even if it is Mr Scott can deal with it, he's a capable pair of hands; on the same basis the source probably isn't the science class: if there was no teacher in there it wouldn't just be one scream it'd be utter chaos, which it isn't; so she decides to quickly check in the bathroom...
There's a distinct possibility that a crack in space-time means that an escaped student's just found the other Mrs Kringle with her hand stuck down the toilet; or worse, a floater.
Either way, it should only take a minute to deal with, then she can go get those copies of Dr Seuss she left in the car.