Yes it is not a sneeze...sneezes create more of a one-directional ash-splatter.
This was caused by the very common "stationary ash-tray flipping" that occurs when something comes down hard on one edge of the ash-tray, prompting it to flip basically in place, and blasting ashes in more than one direction. Here, the culprit seems to be his left hand. Oftentimes, the ashtray lands upright again, as seen in the picture. When hit at weird angles, ash-trays tend to do some crazy shit...
When this happens, it is usually followed by a loud "what...the...FUCK! Seriously? How the...". Although, this exclamation pales in comparison to those times when it's your coke-plate.