Tony was in his lab tinkering with his suit, AC/DC blasting at full volume

You walked down the stairs to the lab typed in the code and opened the door to the lab walking over to where Tony was locked in so much so he didn't even notice you had walked in, and you were looking at the suit seeing what he was doing and when he looked up to get a differ tool to try and fix the suit with he jumped cause he didn't see you there

"Geez kid your gonna give me a heart attack"

He said telling J.A.R.V.I.S to turn the music down