Ending was a total copout. (Spolier Alert)

Yeah - her having Mac killed was really rough business.

However, the scene that any thinking, breathing, human being with a heartbeat wanted to see was when Gerry found out his mother was the mole, and how he reacted to the IRA putting a bullet in the back of her head. His m-o-t-h-e-r.

Why introduce a major character, have the final act pretty much revolve around his decision - and then just have him disappear never to be seen on screen again? he wasn't even referred to again for God's sake!

Total insult to the audience to leave that scene unfilmed.

They wanted the horrible shock, but they didn't want to do the work of making it believable by figuring out how to write the end for that character.

Simply put - a cheat.

Too bad. Was generally a pretty good movie.