Thanks for playing! :)
At the end of a turn cycle the sniper deals damage to a random enemy that's adjacent to an ally. The damage isn't lethal, and I never got around to adding an animation to it. So it certainly doesn't provide a great user experience as is.
While the base combat all occurs in melee, the sniper does more damage with its action when there aren't any adjacent enemies - giving it some incentive to stay out of the fray!