Does Harland just disappear after that quest?
Yeah, he is down on the launch pad in the game with the others as they take off.
That's what I find weird about it, it doesn't fit in.
I mean, he doesn't believe in Jason, he thinks Jason is a nut.
What could possibly change his mind to want to go with them at the last second?
So yeah, he 'apparently' goes with them, but I think it's incoherent and would rewrite it.
[edit]
Oh yeah, and I'd like Dead Sea as a companion.