Quicksilver telling him to hurry to catch a fellow speedster was probably one of the dumbest suggestions Iron Man had heard in an altercation. He just muttered, "Right," rolling his eyes and taking an easy stroll towards the stairwell. He heard their voices at the same moment he saw them, making him freeze and hold a tight fist at his hip, ready for whatever this guy wanted with him. He already felt claustorphobic in this space. This needed to end quickly.
Without wasting precious seconds warning Quicksilver or taking the time to talk this over rationally and find out why exactly anyone thought it was necessary to break into his headquarters and make an awfully rude mess, Iron Man just queued up his screamers to fill the hall with a debilitating, high-pitched shriek. The noise was enough to have SHIELD agents five floors above covering their ears, and making the some of the ones stampeding up the echoing stairwell keel over and vomit with the vibration in their bones, putting a quick end to that troop.