I literally check every body so I'm able to get this achievement lol. Hopefully it happens. Someone mentioned the throwing the guy off the roof but if you keep talking to the girl you have another method of getting rid of him ;)
So, say I blew up a wall with a grenade because I didn't have the 'punch through a wall' upgrade. And there was a dude standing on the other side that I didn't know about. What are the chances of him just having been knocked out? Only potential death so far...
I know exactly what you're talking about with this because I wondered the same exact thing. I actually noticed that after this Zzz appears when they are knocked out and a skull appears if they are dead. I saved before to experiment and I shot him in the head lethally on purpose with a pistol and the skull appeared after. Hopefully it doesn't count if what I saw is correct.
I don't usually drink till I black out, although that happens on birthdays (yay for birthday shots). Usually though every Friday night and the occasional Saturday. I don't know why but I just don't drunk during the week.