Its just Dave being Dave in true Dave fashion.
While performing last night at a show in Vegas, Grohl motioned to an audience member to pass him a beer. He then places the beer on an amp and attempts to drink it from the amp while playing. This didn’t work out so well, so he picks up the beer, chugs it and heads back towards the stage. After a slight misstep that turns into Dave falling off the stage, he jumps right up, gets back on the stage and continues to play.
