One thing to note here, when that dude asked Kali what do you want to talk about and came back into camera view, he was ready to go and I don't think it would have ended well for Kali.
I have no idea about the outcome - I think BB says this Hopkins guy is ex-forces/MMA? But now I've watched it again I think you're right about him switching when he turned round
There are GetBig combat experts who could explain this better than me

, but anyone who's done any the most basic door self defence/de-escalation training can see initially he was minimising direct eye contact, over-smiling, etc. But when he walked back he was advancing square with fixed forward gaze to within 'pecking' distance (aka headbutt range LOL). At that point he'd made his mind up