Aw jeez, they could have gone out with a solid 10 if they'd have left it with the four of them sitting there, condemned to spend the next year locked in a jail cell with just each other for company. Straight out of Sartre's "NO EXIT"!! That would have been tremendous.
But they totally blew it with that final 60-second "prison monologue" bit. Being left with the idea of the 3 guys in a regular prison situation simply isn't as Seinfeldian a concept as the thought of all 4 of them trapped in their own little private circle of hell. So -- final score 6.
my $.02
Michal