Er, this is not really an error on the developer's part and not really an error of any kind, more of a rather amusing way of keeping the flag really. I was playing tonight on Silo and I had the flag, the enemies were approaching fast so I headed for the elevator, when it got to the top, immediately after the ping sound I pressed the button again to go down, and then again when it got to the bottom, nobody could shoot me or get into the elevator. It was very amusing, I noticed someone else put "LOL" as well, I think it was the guy that was trying to shoot me, at least he saw the funny side, anyway he did eventually manage to get in when I miss-timed closing the doors. I was thinking that you could probably put a 1 or 2 second delay before the button works again as this could actually get annoying after a while.