why did Colette's bomb at the beginning not go off?
was it intentional? it doesn't seem like she wanted to get caught - but maybe she did and this movie was a long con to draw out a mole since 1982, and when she found out it was her mom, she was upset and killed Mac (or might have wanted to kill him anyway to be free)? or was it just an accident and the film played straight, as it is shown?