The double-EXRM0 is what ScottKit calls swap_room and you’re right, it doesn’t make sense except that it’s the best* available workaround to ScottKit Issue 38.
We discuss this a bunch in what started out as a thread about the 99 message limit and then turned into a thread about ScottKit’s iffy management of situations requiring continue. (Casual glancing at a couple of decompiled original SA games suggests that he does in fact use continue a little differently for lengthy actions than SK does, but aside from being inefficient I’m not sure there’s anything wrong with continue-inside-continue. In any case it’s a compiler question.)
As for running on a TRS-80, yes, I agree, but I couldn’t find an accessible workflow to test it and try to make that happen. Do you have one?
*- okay sure all of the other workarounds were equally pretty but I wanted to pick one and stick with it, and that’s the one I picked.