Exactly. I think anyone can use Kap but he really decimated a team with experience.

Overtime I've learned to expect which side and angle an attacker is most likely to come from and which paths they normally take based off objective.

There are a few instances though people over look due to other background objects and you'd think they see it but they don't.

Such as the garbage can on the outside of stock trading room, south 2nd floor bank. Right side of door on hallway side. An attacker should see it from either side given the angle and placement but I have yet to not get someone with it that comes through there for both a CEO office or an open area(cubicles) defense.

Baiting is also useful. Sticking with bank. If defending CEO or open area(cubicles), I'll put a trap on terrace door left side facing into skylight stairway and remove the barricade. Attackers are confused/worried about a run/etc.. but they don't look and sometimes I'll catch 2 or 3 with one EDD as the rush into an open door.