I know that with a baton or a charge prod I can knock out a fellow from behind, but I never did good use of a crossbow without revealing myself post-shot.

Do I have to master the pistol skill? is there another way maybe?

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1 Answer

As @GeoffAtkins said, a headshot will incapacitate the enemy immediately (or at least very quickly) and unless there is somebody around to witness the person falling down no alert will be raised. To reliably land headshots a good pistol skill level is very useful. Also useful: The accuracy mod for the crossbow as well as laser and/or scope.

A word of caution though: Later in the game several enemies will wear helmets which render them immune to headshots with tranq darts.

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