It's interesting – if you carefully complete all the tasks in the last (very last) mission, there are indeed creatures standing near the claw, but it's still a negligible amount! The feeling is roughly like this – against a wall, you know what happens.... And, characteristically, the same situation was in the last mission of the previous expansion (Hammers of Fate)! It seems they just run out of ideas – they create the last mission on the verge of impossibility, and in doing so, ruin the game!