The Tower was the last place he wanted to go that day, but it was one of his only options. After his last mission it was becoming increasingly difficult for him to use his prosthetic; he could barely move his fingers, and every so often he would get sharp pains in the joint where metal fused to flesh. He could go to S.H.I.E.L.D., sure, but there would be mounds of paperwork and their engineers weren't necessarily the best with something attached to a living person . . . And besides, S.H.I.E.L.D. meant chancing a run-in with Steve, and that was the last thing he wanted to deal with after everything.
And so, that left the Tower, and Tony Stark. If he could survive the snide comments without punching the billionaire, it would be worth it. And so James sucked it up and stepped inside, the arm stiff at his side as he went looking for the engineer in question.