What decision is made when F2 obstructs B4's swing during a play with two outs?

When F2 obstructs B4's swing during a play with two outs, the correct decision is that B4 is awarded first base and R2 is awarded third base. This is based on the rule that if a batter is obstructed while swinging at the ball, he is granted the right to advance to first base.

Additionally, the rule states that base runners are given the opportunity to advance when obstruction occurs, particularly in situations where the batter is hindered in their opportunity to reach base safely. Since there are two outs, this scenario also emphasizes the gravity of the obstruction, as it could impact the game's outcome significantly. The advancement of R2 to third base reflects the principle that, when a defensive player obstructs a batter, the offensive team is afforded some compensation, allowing their base runners to move forward. This decision aligns with the intent of the rules to maintain fair play and provide opportunities for the offensive team after a defensive infraction occurs.