(Well, it's true that the hobbos can probably hear this whole mess coming with the portcullis and know to stay reasonably quiet.  On the other hand, there's nine of them and they're all in various forms of armor.  I'd think they'd be in position and no longer clanking too much by the time the rogue finishes with both traps and gets to the door, but the marshal may have had to make noise in positioning everyone when he realizes that the heroes are here<em>right now</em>and they're probably flanking the door by now, so either ruling works.)