Rahane had no control of either shot. In real time it was difficult to see if the ball had taken glove / armguard or both. Especially the "catch" by Watling, ball looped slowly which is normally what happens from glove. So yes, I mean he had some luck that the ump didn't give him out.Lol. He wasnt out but he's lucky because the umpire may have ****ed up and given that out on another day.
When you keep giving an ump a chance to make a decision, sometimes they make a decision.