Normally I would call for a teamwork test but Doc has enough successes on his own that it's not really necessary to add any more. Doc knows how to build ice caves, igloos, and the like. He also knows not to build fires under trees (the rising heat melts the snow and ice, which then falls on your head) and not to let the exhaust pipe of the van to get blocked with slow, lest you kill yourselves with carbon monoxide. And so on. Go ahead and RP your expertise.
@Zweiblumen: Survival is linked to Willpower, not Intuition. However, Doc's Willpower is the same rating as his Intuition+Ganglia, so the end result is the same.
Doc does not have to act erratically. As I stated earlier, Chino does not have to continue acting erratically either. Feel free to do so if you think it makes for interesting RP, or just keep doing what you're doing.
OOCly, one of the possibilites of CFD is that you can have multiple strains of nanites fighting for control. Eventually, one strain wins out and the personality is more established with less variability. Perhaps Chino is still in the "nanites battling for control" stage while Doc has progressed beyond that and is in his final form. Or not. It's up to you, as I didn't want to put myself in a position where I was bossing people around about their RP.