There are a lot of different trajectories to take if youâre trying to establish a career in Hollywood. Some actors seem to break through pretty quickly, while others take a bit longer to build up a presence. Kate Mara did the latter, by appearing in smaller roles in films and TV shows over time. One such role just happened to be on screen, albeit briefly, with Robert Downey Jr. in one of the biggest movies of 2010, Iron Man 2 — and she recently revealed exactly why she chose to make that particular move.