M*A*S*H: When Henry Blake is going home. The whole scene where he's saying goodbye to everyone. Then when he's about to get on his chopper, he sees Radar saluting him. He goes over, returns the salute, then says, "You behave yourself or I'm gonna come back here and kick your butt." Then after the commercial break, they're all working in the O.R. And Radar comes in and reads a telegram saying that Henry Blake's plane was shot down and there were no survivors.
M*A*S*H: When Radar goes home. Just as he's about to go to his going home party, choppers arrive loaded with casualties. So everyone says goodbye to Radar as they're performing triage. Then when they're all in the O.R., Radar looks in on themk one last time. Hawkeye looks up and sees Radar looking through the window and salutes him. Radar salutes him back then leaves. The very last scene, Hawkeye, BJ, and Col. Potter go into The Swamp for a drink and find that Radar left Hawkeye his teddybear.
Armaggeddon: The scene near the end when Bruce Willis stays behind to set off the nuke manually.
Deep Impact: When the astronaughts decide to make one last attempt to destroy the comet, and say goodbye to their families because the attempt will cost them all their lives.