I want to add my experience as it differs a little from the OP's video.
I'm on PC and what I did was talk to Darius. I saw him walking away and noticed that he had bronchitis. I immediately went to the nearby safehouse and made a medicine for bronchitis.
When I walked back, Darius was standing at the place where he's supposed to be (according to some youtube videos I watched) but I don't get a red swirly prompt to eavesdrop at the metal gate.
Hope this is somewhat helpful for the Devs in figuring out this glitch.