During the final (?) confrontation, when Seeker defiantly states that he will not give up the cube, the game may crash with the following assertion:
scummvm: engines/tsage/converse.cpp:251: virtual void TsAGE::SequenceManager::signal(): Assertion `_sceneObject' failed.
It seems to depend on who is the active character when I enter the room. I couldn't reproduce it as Quinn, but so far it happens every time as Seeker. (I haven't tried as Miranda.)