I can't comment on the legality of what the bus driver did or didn't do. But I've been riding for a long time (45 years :afm199) and I finally got the the point where it doesn't matter whether or not what the other person does is illegal or not. The reason is that if a driver does something illegal, and it kills me, the fact that what they did was illegal won't cause me to not be dead.
In the situation that your friend faced, I would have split the lane too. But I would have stopped by the door and "walked" (Fred-Flintstoned) the bike past the door. BTW, I'm one of those people who NEVER puts their feet down unless I absolutely need to. As soon as I leave a light, my feet are up. If I come to a stop sign, I stop and keep the bike balanced and keep my feet on the pegs, then go, etc. . .
But for something like this, where it's just so sketchy, I will "caveman" it, at like one MPH. At that speed, and since your are walking the bike, even if you get doored, not much will happen.
Others folks might not agree. I haven't seen anything in any of the books about this technique. And it's possibly bad (slippery roads being one reason). But it's been working for me. Never been doored (yet).