I gotta say charging the armed man and trying to take away their shotgun seems like a really, really good idea to me.
I probably wouldn't turn in a completely different direction and try to run away.
And never, ever, in a million years, would I pull out my phone (assuming I had one) and call the police saying I'm being chased and illegally detained, then stop at a distance, keep my hands in sight, and back away if need be to keep distance, until the police showed up. If I had no phone I absolutely would not request they call the police. Nope. Not ever.
The MM boys see you reaching for and pull out what’s obviously a gun (your phone) and shoot you to death.