Although drinking might make you more prone to an injury, like falling from a rooftop, getting into a fight, that same alcohol might help your injuries not be so severe. To be fair: this means that if you get a life-threatening gun shot from a bar fight, being drunk helps you, but you probably wouldn't have gotten shot if you were sober. Here's why this happens:
When we get injured, our bodies go into an emergency preservation mode, which trips a series of physiological panic buttons that can ironically end in death. Alcohol, however, seems to make the body not hit those panic buttons as hard or as much, helping prevent death.
The research found a correlation between the upper levels of intoxication and lower mortality. It means that for this to work, you have to be wasted, so don't try to use this research as an excuse for doing dangerous stuff while drunk.