Star Wars tower battle — then, composing the battle music

In the Star Wars universe, we are in some sort of final battle sequence. (It's unclear whether this is an immersive video game or possibly a movie shoot.) The battle is on foot, in the area in and surrounding this gigantic castle-like tower, whose depth stretches down for what looks like hundreds or thousands of feet. At first, most of the fighting takes place on the "ground" level, which must be little more than a platform in the open air for all that depth below it. I'm taking down storm troopers left and right with my blaster, actually banking my beam off walls to hit them.

At one point, a guy rolls by in a souped-up motor scooter; apparently he was a minor cast member from the X-wing fighters that destroyed the first Death Star. This reminded me that this might be a movie shoot.

The battle starts to escalate. People begin entering the tower, or falling below the platform and using long grappling hooks to hang on or get inside. The only structural detail I see inside the tower is a very spacious stairwell that begins at the outside edge near the bottom of the tower and spirals slowly up for an unknown distance. (Even at the bottom of the tower, the ground below is still not visible.)

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Somewhere on the outside of all this, I and a band are jamming/composing music to go with this final fight scene. Unfortunately I can't recall a single note of it. Seems like I swapped instruments with the "new guy" just as we got to the solo or bridge. Can't even remember who was playing what instrument though.