I have put a more thorough description of the problem in the discussion topic for the puzzle, but the bottom line is that I believe the wording of the problem is somewhat misleading. Specifically:
“The game ends when … Indy finds himself in the same room as a rock on the same turn: you have failed”
When I first read this, I wondered to myself, “What happens if Indy and the rock go down two different paths in a Type 4?” According to a strict interpretation of the above statement, Indy would die.
I didn’t get to experiment with the Type 4 example, but if Indy enters a Type 9 from TOP at the same time a rock enters the same room from RIGHT, then Indy will not die. This is not immediately obvious from the description of the puzzle, especially since:
“If a rock hits a wall or gets stuck, it will be destroyed and dissapear [sic.] from the grid ON THE NEXT TURN.”
(Emphasis added.) My interpretation of this is that Indy and the rock share the same room for a turn, even if the rock hits a wall.