After Daffy Duck nails the board over Speedy's hole in the wall, he nails a second board (with "Shut Up" written on it). Initially, the second board is not only over the first, but it is also on it as well. But when the scene switches back to the boards, the second board has move up and over the first. It is no longer on the first, even though it was nailed in place.
When Daffy is using a plunger to suck Speedy out of the hole, Speedy places a stick of dynamite out to be sucked up instead. But when he lights the fuse, even though the suction is strong enough to pull the dynamite toward the hole, it does not affect the lit match. The flame continues to go straight up instead of being drawn toward the source of the suction, which is where the stick of dynamite is being pulled.