There was an attempted takeover of the helicarrier. There weren't many people on the helicarrier, possibly because it was in for repairs -- my memory's fuzzy on this part.
Tony was free and moving around the helicarrier. He got to Clint's room and found a rifle that Tony designed and could take apart and put back together in his sleep. Tony's happy because he has a weapon now that he knows how to handle.
There's a scene in a lab and the bad guys are there standing guard over a couple of doctors and Bruce.
At some point Tony and whoever else is free flood the helicarrier to stop the bad guys.
There's a scene I remember where Tony's in a tilted hallway after the flooding has happened, leveraging himself up using the rifle, Clint's there at this point, sees that, and is not happy with how Tony's treating his gun, Tony calls the gun an outdated piece of junk, and Clint praises the gun as the most amazing thing ever before realizing who he's talking to.
I really want to re-read this story. Please help. Thank you.