The goal here is to get to the ladder up in the northeast. Is there any way to know which doors have progress and which ones send you straight to the damage floor room at the start? Why, you go through the doors, of course!
Oh, and those one-way door segments behind the ladder each have the two rooms without damage tiles spiked with forced encounters. Which you can't run from because there's nowhere to run to. Have fun!
(What makes this the fun kind of cruel and not the frustrating kind is that this map is small enough, even discounting the 3x3 space that's obviously for later on, that it doesn't wear out its welcome)