Answer:
the person who plays Modern Warfare will compensate his roommate for loss of sleep.
Explanation:
Coase theorem states that both parties want to maximize their efficiency and benefits but opposing behavior may arise conflict between two parties. Like in this example both one want to maximize his fun and benefit through playing and other one want to maximize his benefit through sleeping. So to maintain overall efficiency the roommate who is playing games have to give some compensation to other roommate for overall maximization.