I thought maybe to direct and communicate with the men loading firing and aiming the gun because of the sounds of the battle traditional communication may be extremely difficult. But he seemed to not really be looked at or focused on by the men firing the gun so I don’t know.Also it’s the 2019 film
I've been trying to gather some more specifics for you and am hoping you can give me some more details.
If you can't find a clip, can you confirm that what you're looking at appears similar to what you see briefly at the :49 mark of this clip of the 2019 movie? It's a Japanese antiaircraft gun but sounds like what you're looking at.