In The Dark Forest, p. 298, Cixin Liu's character, Rey Diaz, described a dead man's switch.
Rey Diaz brought down his left hand and covered the cradle with his sleeve. "I was taught this wonderful idea not by an expert in nuclear strategy but by an American film. In it, a man has one of those gadgets that sends out a continuous signal, but if his heart stops beating, the signal is terminated. Another man has a bomb strapped to him that's impossible to remove, and if the bomb doesn't receive the signal, it'll explode. So even though this hapless fool doesn't like the first guy, he has to do everything he can to protect him. . . .I like watching American blockbusters."
What is the American movie that this passage refers to?