We had the same rumours going around about our Paras and SAS.
I won't give them any more airing here, but the only thing that sort of helps me understand those people is the training they have to go through to get into those regiments.
These guys have to undergo god knows what, and are actually encouraged to be a law unto themselves, with no fear or squeamish factor tolerated.
The Paras actually aim towards creating "bloody havoc" (their words) when they are in this sort of snatch/hit squad scenario. The more chaos and fear they can stir up, the better.
The SAS are just out and out nutters when in action. They are specifically handpicked for those sort of qualities. What on earth those guys do when on the job, god only knows....but it must be said that they normally keep a tight lid on their comings and goings.
In the end, we train these guys up to be human pitbulls, so should not really be surprised when they go overboard.