Taken the device away from the guy he'd given it to in the first place. Most likely to transport into the vacuum of space where the sound can't travel or contain it somehow (since by the time the heroes arrives, as we see in the previous issue, it's spreading like wildfire and nearly all of Mexico City (iirc) is the victim). If Qubit had been there at the start, he might have figured it out that much sooner and saved thousands of lives. We don't really know what he could have done, but that's not really the point. The point is what he, the Plutonian, thinks he could have done and how it affected him afterwards.