Fans of last season’s runner-up Bryan Voltaggio had their dreams fulfilled by his guest judge appearance. Photo from Bravo. Last night’s episode of Top Chef may as well have been called “Couples’ Retreat”: everything seemed to be about twos. We got a quickfire where two lucky chefs snagged $10,000 each and an elimination challenge where teams won and lost in twos. And if we’ve learned anything from seasons of watching Top Chef, it’s that…