SPOILER WARNING


once you kill Sam at the VERY END of the Museum (in the circle room where he pops up in the middle of the divides) you have to shoot him one more time and then he is almost dead and he is bleeding alot as he is walking to get out of the museum. Sam is on the second floor all bloody and Tom is on the top floor, they exchange words and Sam said Tom could never kill anyone, and then Tom shoots him.

It cuts to about 20 years later with TOM as an older man watering his lawn, 2 guys pull up in a car and ask if he is Tom, he says yes and they say "Don Salieri sends his regards" or something like that and then they kill him.