Absolutely.
We don't call 911...
Call 911 and do what you have to in the process. Better if you let law enforcement know what is going on. If you are in a position that you can't call 911 do what you have to then call.
Course you do. Someone's gotta remove the body.
I do. They come and take away the (former) criminal, although they leave the bloodstain. "Shoot, shovel, and shut up" sounds nice and may have its place in life, but I don't want to be halfway through digging a hole six feet deep when the police my neighbor called finally show up. I also know what to say to the police when they arrive and when to stop talking and wait for a lawyer - almost as important as frequent range time. As for calling the police while cowering and hiding, no, I don't see the point. Even if the police could get there on time, society is better off with one criminal fewer. I will stand my ground.
I called 911 - not so much because this was an emergency, but to point out that if the po-lice hopped right on by there was a good chance the clowns would still be within blocks.
A deputy showed up almost two hours later, pointing out that he'd been across town 'running an errand' for the captain. Opportunity lost, for sure.