Okay, I've tried all methods I could think of. One of them worked. It goes like this: Rename BLOCKS.002 and SPRITES.002 to BLOCKS.000 and SPRITES.000, then you make a level and save it as LEVEL0.000 and it'll run fine with Medivo stuff. I bumped into another bug, though. For some reason, if I spawn at the bottom of the map -- even if there's a block between me and the bottom of the map -- it bugs and instantly kills me and makes me fall through the floor. Any ideas?
EDIT: I just added some stairs that go really high -- they still act as if they aren't masked tiles. Is it mistaking the masks of Medivo for the ones on Diamondus or something?