It is not like swilling a bottle of Jack, but it sure isn't equivalent to drinking "a beer" and gargling with mouthwash. A can of beer is going to be about .02. .12 equals about six beers. Factor in the burn rate of about .015 an hour, and you end up with more than six beers consumed, unless he pounded down a six pack in short order, and got arrested immediately thereafter, and instantly took a breath test.