If you know the layout you can systematically sweep the building and kill/capture everyone.
I usually have 2 flying gals take care of the towers while the rest enter the building through the main gate. 2 gals go down (one with a pickaxe/mining laser), there is only one guy there (don't know about JS), while the rest secures the ground level and rests a bit if it was a long walk to the door.
Then two teams, on for each stair, go up and we clean one level after the next. If some tower police didn't show themselves to the flying gals we break through the doors here as well to get them.
I used to lasso everyone, but that might be more difficult now that they usually pick up their guns again.