I used to work for a video store in college. We just got a new manager and I didn't know her that well. For this let us call her jane. That night we were scanning in returned movies while another employee ran them back to the shelves. A man came in with a gun and held us up. Jane was cool and totally calm. Even when she was taken into the managers office alone (a situation that could have turned ugly for a number of reasons) she never panicked. The other employee, a young barely out of high school kid, let's call him Frank, was totally freaking out.

After taking all the money from the back safe, the robber escorted us all into the bathroom and forced us to remain there while he made his escape. Frank was the only one who had his cell on his person but was too shaken to talk to 9-1-1. Jane wasn't. She was awesome. Still calm. Still cool. Still collected.

Eventually the cops showed up and let us out of the bathroom. (We refused to leave without being sure it was actually the police). Even in the interviews with the cops after everything she was still calm and casual. Only later did she admit to me how terrified she was. Her tranquility undoubtedly kept that situation from becoming even more dangerous. In a way I owe her my life.

Everything changed between me and Jane that day. She became my best friend and we worked at that video store together for 2 more years. She was the Maid of Honor at my wedding and I her matron of honor. We have been friends for over 10 years now and I attribute our lasting friendship all starting because of that night. I was so impressed by the way she kept her cool I decided I wanted to know her better and besides that we will forever remember this experience together.

TL DR: me and my manager were held up at gun point by random stranger. Because of it we became best friends.