Just to add one thing... Romo needs to see every single game-situation... and that includes running the clock out when you're up big in the fourth.
Parcells will want to see if he can maintain his focus in those situations and continue to take the snaps from center cleanly and continue to hand the ball off smoothly and crisply to the running back, and not make dumb mistakes that can let a team back in the game.
It sounds too simple, but I assure you it's true.
Also, ask yourself... how many times have you EVER seen Peyton Manning or Brett Favre come out of a game regardless of the score? I'm sure it happens occasionally, but not often. You ALWAYS see Peyton taking the victory kneel at the end of games... never Jim Sorgi.