Go the part where Porthos tries to hang himself and it doesn't work. Then he accuses Aramis of sawing the beam. Now look closely. When he says that, he has a rope around his neck. Then Aramis tells him to put some clothes on and gives him his cloak, or whatever it is. Then the camera switches back to Porthos. Look at his neck. There is no rope, and it didn't show him taking it off either.