This is an original game bug. I can reproduce it in DOS and ScummVM with KQ3 2.14. It occurs in at least this room and the staircase room 64.
This bug does not occur when *climbing* the ladder, it occurs when *falling*. You're already dead when it happens, and you can still Restore. I'm updating the title and description.
The problem in both of these rooms is that there's a black priority line that overlaps with the fall path. When falling from the ladder, the black priority line is at the base of the tree that is behind ego. In cave room 64, there are several.
If ego falls at the right place then his movement doesn't advance, because AgiEngine::checkPriority returns false if ego is on a black priority line. This causes AgiEngine::updatePosition to reject the new position and roll it back. This happens forever.
I'm attaching a save game of the ladder falling in progress, and a save game in staircase room 64 where walking straight down will reproduce.
I don't think this is worth a workaround. Even if we had a script patcher, it doesn't seem to be a script bug, but an unfortunate placement of black priority lines that are unrelated to falling. I see no property that could be set to prevent the priority line from blocking the motion. (There may be a potential patch, I'm just saying that even if we could patch scripts, I'm not sure what we could do.)
Given that this is original behavior that occurs after you're already dead, and isn't easily fixable without cluttering up core motion code, I think it should be closed as wontfix.
