We're up on level 286 and my legs hurt like hell. They've started to change from office floors into labs (shouldn't those be below?). At any rate, I haven't found any chemicals or whatnot, but there are Bunsen burners. It doesn't really help, but it makes me wonder why they're even there.
We're more than 3/4 of the way up the Tower, and the walls are starting to change again, so I think it's going to switch up again.