Training with a partner can make the time spent exercising totally fly by just as it ups the intensity level and helps each improve their performance. The Army of Two workout is an exercise in synchronized muscle control. Not only do you have to perform each exercise but now you are doing it together. You can disrupt each other's rhythms or balance or work together to amplify them so that you gain in power, perform every movement in total sync and really become like an Army of Two capable of taking on the world (as long as you are together).
Extra Credit: 30 seconds rest between sets.