Bruce was already nervous about meeting Pepper. Hell, Bruce was nervous abut going out to dinner by himself in case someone recognized him. Was it possible for someone to have PTSD from a very public trial? Maybe. As nervous as he was about Pepper he certainly wasn't expecting another redhead in the room (or anyone else for that matter) and stopped in his tracks right in the doorway all awkwardly when he spotted Natasha. Then he shot Tony a very pointed look and made a nervous sound with his throat, forgetting his manners completely.