Why would Leon be nervous about Alan finding out he fucked Clara? Is Alan going to beat him up, tell mommy on Leon, or tell the director "hey your agent fucked my wife"? Leon isn't afraid of Alan or he wouldn't have openly been trying to seduce his wife. Hell if anything Leon would probably rub it in and tell Alan in detail how he fucked his wife's brains out, made her orgasm like Alan never could and creampied her to finish it off, mention how she has been hiding it and lying to Alan, gotten closer and shared her deepest secrets with him instead of Alan. What's Alan going to do about it? I'm quite sure Leon would wipe the floor with Alan. Not too mention depending on what Alan does he could blow the entire mission and put his beloved cheating wife in danger. So why would Leon be nervous or even scared?