Am I imagining this overwatch presentation?

I vaguely remember a segment in a blizzcon, or dev update video where they showed footage of the sound team firing a gun in different locations (I specifically remember someone firing a machine gun down a hole in a concrete building) to sample the sound of shooting in different locations in-game (buildings, outside, etc.). Does anyone else remember this happening? Am I thinking of a different game? Am I imaging a scenario that didn’t happen? Am I even real?