So true, it really is amazing that you don't even notice the exercise when combining it with something funny/purposeful. I was in a milsim game some years ago, in a room at a military training site with my mate, and suddenly we see something thrown inside the room, and we just know that we gotta get out, so we scramble for the door only to get stuck shoulder to shoulder getting shot in the back by a guy in the window. The "grenade" was a brick .. :)