Arkas was accounted for back in the very first chapters. He built the buildings. Etho didn't like talking to him because all he did was build, remember? (and not sleep. Arkas didn't sleep)

Mhykol was talked about (ie - he's over there we need to check on him) but no one saw him because Doc knocked Etho and Nebris out before they saw what Pakratt was up to.

I dunno if you'd want BTC trying to save everyone :>