Yes, I have a difficult time believing both officers abandoned their post and risked and punishment by superiors just so they could rush home to Hendren's apartment to drink a beer and play Russian Roulette.
I also don't understand how they got started on this alleged game of RR. Is that something people do when they're sober or do you have to be pretty drunk? They hadn't been at Hendren's apartment very long when he shot her, probably less than 30 minutes. It certainly didn't seem to be enough time to get drunk enough to play RR, unless they were shooting beers or drinking shots of hard liquor. Seems you wold need to do something to screw up your courage for that game.