When you return to the main part of the room with the guard in the south box, he has no path to you (except across the force arrows, which block the brain pathmap) so he will be moving unbrained. He also rejects any moves that put his sword onto a bomb.
This means that indeed, guard at (24,22) facing NE is a fail state. There are a couple of different ways to prevent this happening:
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×1. Bring a keg into the south box with you, and use it to block the guard's motion towards (24,22).
2. Drag the guard to the west end of the south box and run for the trapdoor while he is still far enough west that he gets over the force arrows.
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50th Skywatcher
