I also used hackmove with Johnson, but just to get him past the stairs. I swear, all I used it was on the stairs and he followed me all the way back to Monitor. I left him at the pub.
He stayed there and the game seems to continue without incident (I am not finished yet) and doesn't seem to realize he's already back in Monitor, because when I talk to him I get his "Don't waste time, let's get back to Monitor before we get eaten" speech. Then he starts following me again and I have to lose him.
Guess I'll try taking him back to die...
I second the idea of sending him back to Monitor though if he survives. Why not tie up a loose plot end? Lots of things about SI annoy me, like the lack of good subplots, and the way the game forces you to stay in one town for such long periods of time, and you don't get full mobility until you almost really don't need it.
But it would be funny to see Johnson as the last vendor in Monitor alive after the Banes. Maybe he and Harnna could shack up.
![Wink ;)](./images/smilies/icon_e_wink.gif)