well maybe that was for sidequests. I feel like it's something you'd play again for sure.
I got to the lift in the Underdark on Sunday and it basically told me to turn back, so I knew I'd missed a lot then.
bitterly difficult were the words it used.
It looks like I haven't been able to find an infernal mechanic because when I saved the grove, they left for BG.
apparently you can find them in Act 2 & 3 as well and I don't think I got them killed. .