But on the other hand, why would Sakura have had any reason to fight? Ogami's intention was to kill all the gang members; she didn't want anything to do with that.

My theory about what's going to happen is that Ogami kills all the cops but gets hurt in the process, so Sakura, way against her better judgement, grabs him with her freakish strength and runs. Angst and characterization ensue. Because in Kamijyo, you can't have characterization without angst.

They only got away with the scene where Doumeki explains why he sticks around with Watanuki because they're CLAMP. No one else could have pulled that off.