So this guy gets his arm trapped hiking a slot canyon near Moab, and it is now a movie.
I've done lots of canyoneering up there, and rock climbing, and sometimes alone. I guess I could have been in that same situation.
Here I am at the summit of "Ancient Art" last April:
And a cool video of some other people climbing it and then jumping off (I rappelled down, I'm not that nuts)
https://www.youtube.com/watch?v=erfCL-ZfZhY
However, looking at this guy's situation, I would not have done something that remote without letting someone know where I was going to be and when to expect a call. In addition, I now always have my Delorme PN-60w with SPOT that sends a location signal via satellite every ten minutes so that even if I wind up in a place where I can't send a distress signal (such as down in a slot canyon like this guy was, or unconscious or too injured to use the device) my wife can look up my last locations on a web site and tell rescuers "well, at such and such time he was at this location, and before that he was here, and here, and here, so he must have been heading that way".
Here's an screenshot of the map of the ride I did last Monday. Now this is not from the GPS, this is from the satellite tracking service that anyone with the right password can see, live, anywhere in the world while I'm riding/hiking, etc.
Of course the other advantage of this GPS/SPOT device is that I can send a text message to my wife and let her know I'm ok, or that I have a disabled bike, but that I'm fine, even where there's no cell reception (which is most of the time where I ride). It both gives me peace of mind to go further and longer than ever before, and my wife knows that she's always just a web site away from knowing where I am anytime she wants to (while I'm riding, let's not get carried away here) :)
I guess I just never want to be in a situation where I have to cut my arm off to save myself...