Indian media have fanciful imagination. Border police have tasers and tear gas to apprehend and break up illegal entry groups as non lethal options, while Army soldiers have combat knives and rifles. In some circumstances, the army might take police equipment.
I don't believe for a second that PLA would attempt to engage Indians in medieval reenactment combat.
What seems more likely is that they ambushed an Indian incursion with intent to capture the leadership, partially succeeding but leading to some Indian soldiers and an officer being shot dead in the struggle. This is what caused the initial report of 3 as opposed to 20 casualties.
In the confusion, Indian soldiers might have believed that the PLA meant to kill them all and they scattered all around the mountains, some not even taking their equipment with them, this led to another 17 deaths and injuries caused by the environment.