I think they'll certainly go to the break.He seems to be able to open a gap on Carthy when the stages end with an uphill sprint but think there's only a couple more and they could go to the break.
He has his stage win. 4th place would be his career-best GT finish. This race is already a success if he doesn't move up on gc. But he should definitely try.
It might not be Carthy who cracks, it might be Carapaz, or even Roglic, (although it might also be Dan himself). But I think there are opportunities there for a rider like Martin, if the team ride the final week clever.