Seems like a fistfight gone out of control on a ridge, which eventually resulted in the ridge collapsing.
What the sequence of events seem to be (leaving out any speculation part, stating only whats confirmed from various authentic sources)
- Patrol party of 16 Bihar Regiment, went to check compliance of agreement of Patrol point 16, which they found was not done by PLA & were blocking the path on the ridge, pushing & shoving started, possible rods in play, once the first fatalities happened, most likely was the CO, there was no way to stop the fight which followed later for some time.
- India troops called in second patrol party, which quickly arrived, and so did Chinese Second Patrol party shortly afterwards.
- Eventually the Rigde collapsed, many from both sides fell.
- 3 Indian troops were dead before reaching hospital, 17 died of injuries later due to fight/fall/sub zero temp of overnight, before they were rescued. Many fell in river & got out later or fell to injuries.
- Chinese side too fell of ridge, there CO too died, river flows towards India side, 43 Dead chinese soldiers were counted , Chinese Helicopters were allowed to fly inside India to pick up dead & injured
- With the ridge collapsed, the remaining Indian soldiers on other side was released by Chinese, just like we allowed them to pick up dead & injured.
- Other than 20 soldiers confirmed dead on our side, 3 are still missing, chinese dont claim to have them, possible yet to recover from river.
- Similarly 43 Chinese Dead was found, few more may be found later as the river flows