Corrected entry: In the scene where the X-Men are trapped inside the Statue of Liberty, Wolverine slides down the outside and stabs his claws right through the wall to stop himself falling, and they go in between Jean Grey and Cyclops' faces, which you see from the inside. In the next shot, you see Wolverine on the outside and he stabs his claws through again, to start climbing back up. If you watch where his hand goes, surely he would have stabbed Jean Grey in the head!
Corrected entry: When Wolverine shows the middle claw to Cyclops at the Statue of Liberty, you can't hear the sound when he retracts it. Still the claw is gone in the next scene.
Correction: We saw in the bar scene that he can extend the claws silently, so there's no reason why he shouldn't be able to retract them silently, too. Although it is kind of odd for him to do that at that point, it's still possible within the context of the movie.
Correction: He never stabs his claw though it again, he climbs the rest of the way up.