A SAT phone, spot and Air Rescue policy is required when taking on dangerous activitys in 3rd world countries.
This first and foremost if you are really going deep. It's no different than learning CPR. The first step is to call 911. I had a friend fall off about a 30' drop, did a bounce or two on his way down, while doing astro photography. He had a Garmin In Reach and he's sure it saved his life. He remembers hitting the emergency button and then came too 45 minutes later when a sheriffs dep found him.
