For sure Kampum, not my style either - the indigenous have a more casual approach sometimes - they often leave someone after just a few minutes - I have experienced this myself with different tribes too. It can be a bit scary especially at the beginning. Now its fine though but you're right - I never leave someone until they are through and resting. In circles, everyone rests and then we eat together afterwards so I always know that everyone is fine before they leave.
As for my young man who had a massive reaction... he had zero pre-existing health problems - I always check!
He presented as a picture of health. Aged 28, tall, athletic and never had any health problems ever. He works out regular, eats well, doesn't smoke and had no allergies. He had come to Kambo out of curiosity and more to accompany his girlfriend than any personal pressing reason. For some reason my intuition went into overdrive and I got a message to go slowly with him. I put on one point to test his sensitivity and within less than 30 seconds, his throat swelled completely closed. He was basically suffocating - it was pretty dramatic! I removed the point and washed the area with water and administered basic first aid (something all practitioners should know) and used a special 'opening the throat' breathing technique to keep him breathing until it wore off.
Not typical but it just goes to show how careful you need to be.