If you rewatch the video it looks like he expects to need to manually rack the slide. He’s not phased at all.

I’m not saying going for a locked slide is the best approach. I’m just saying that it looks like he expected it. I don’t think anyone who is clever enough to evade being arrested at the time of the incident is dumb enough to not practice before hand. Particularly in the most surveilled state in the U.S.

He might have decided quietness is more important than follow-up speed when planning a close encounter assassination.