Virtually the entire show. Aside from the very well-done recreations of the incidents, just about every story involves everyday people or emergency personnel stepping up to save lives. Though this troper has always been most impressed by this police officer who chased down a pair of runaway boxcars that collided with a car and bringing them to a halt before they crushed the vehicle against a bridge.
Here's a nice, specific, badass example. A boy is attacked by a crocodile. He is rescued by, among other people, his father, who gets his arm bitten clean off by said croc. The father proceeds to oversee his son's care, does everything he can to help, and at the end of the segment we learn that he saved his son by punching the crocodile in the face until it let go of the son and attacked the father instead. In a show built basically out of Real LifeBig Damn Heroes moments, he's pretty much at the top.
A woman is assaulted by a rapist her son accidentally let into the house. She forestalls him by asking him to let her put her son in another room, then says she needs to call work and tell them she'll be late. He watches her dial, so she calls a friend and manages to ask him to come over without letting the intruder know who she's talking to. Then, when he looks away for a moment, she hangs up and dials 911, still without him realizing anything was amiss. Keep in mind that she's doing all this having just been attacked, with the person who attacked her standing over her shoulder.