Your logic is weird man. We get it, even if she ran, she might have still been killed. That doesn't change the fact that if you want to survive something, you should do whatever puts you in the best position to survive. If you hear that a tornado is coming, are you going to try and go to a basement, tub, away from windows, etc... or are you just going to sti there like "Oh well, I can't outrun a tornado" and wait to die?
Like others have said, she didn't think dude would kill her. So for her, trying to make a video and get something for her social media was more important than erring on the side of caution. It's one think if a nigga just makes a throway comment about killing you. Hell, you can't even just sleep on that, but that nigga pulled a gun out, loaded it in front of her, and made a comment that pretty much made it clear he wasn't playing. You have to put stock into shit like that. You can't just dismiss it.