In Ocean's Thirteen what for Yen was putting inside of some place after passing through the path of elevator? I didn't get what for Ocean planned to put something there. Because I think afterwards nothing was shown about that.
Are you talking about when he was going through the elevator shafts? He wasn't putting anything inside of it, he was scouting to see if it was possible to access the diamonds via the floor or ceiling ducts. He determined that it would be next to impossible, so they decided to try another method. Hence, the shafts were never entered again.