||mm asked if this was a bug via e-mail. I said:
Yup, I know about this and it isn't a bug. What's going on is just that when you push a bot, that counts as "stepping off" whatever the bomb/bot/player is standing on. So that makes the trap become a hole. The player is able to step onto the hole, because we check whether the player can step onto a tile at the beginning of the turn, when it was a trap. The dalek can't push back, though, because his turn happens after the player's turn, and by then the trap is a hole for good.