Porthos shakes his head at Aramis's 'if'; he hadn't had his dagger on him when he wound up in the hotel, and it's not like he really uses it as a main gauche anyway. He much prefers making full use of his armoured gauntlet, and whatever else happens to be on hand.

So he doesn't wait to see if Aramis is going to lend him one, and does as he's told, instead. He's never been the sort to wait, when invited to attack.

At least he knows that a rapier means fighting with more thrusts than swipes, so that's just what he goes for, forcing himself to take into account how much shorter his allonge is, never mind his stride, and the amount of thinking he's got to put into it means that his move is extremely telegraphed, to an experienced swordsman.