I, too, prefer the Dr. over the Vet, generally speaking. He's just more versatile and survivable with 18 impervious -- he doesn't even need Fortitude with that kind of defense, but even with it he clocks in low enough to add on Protected before even equalling the Vet's point cost. The activation click doesn't concern me because it's USEFUL. Send cheaper attackers to wound the enemy, then run them back to Don for Support. Repeat until he is forced to use Protected, to heal twice in a row, or any means of pushing him to transform, and BAM -- the other side is either actioned-out, half-dead or otherwise just not prepared to deal with a fighter in Don's weight class in the mid-game.