Doohan served with the Canadian Army, and lost the middle finger of his right hand when he was shot at Normandy. 

He did his best to conceal the missing finger during his acting career, but sometimes tribbles happen.

Although technically he was not a member of the Royal Canadian Air Force, he was once labelled the “craziest pilot in the Canadian Air Force” due to things like slaloming a plane between mountainside telegraph poles just to prove it could be done (which earned him serious reprimand).