He Was a Quiet Man
(2007)

Everything that happens in the film after Bob (Christian Slater) drops the sixth bullet in the handgun in which he plans to murder five co workers and himself is a fantasy, including Vanessa (Elisha Cuthbert).

Once his fantasy begins to sour, he snaps back into reality, realizes that he is the problem and decides to save his co workers lives by turning the gun onto himself instead.

His shocked co workers crowd around him as he dies.

Thanks John!