What should happen if the umpire's interference allows R2 to safely reach third base?

In a situation where the umpire's interference has allowed a runner on base (in this case, R2) to reach a base that they would not have reached otherwise, the appropriate action is to enforce the rule requiring the runner to return to the last legally occupied base. The purpose of this rule is to maintain fairness in the game by ensuring that the runners do not benefit from an error or interference that is outside their control.

When the umpire interferes with the play, it disrupts the flow of the game, and it is determined that the runner could not have advanced safely without this interference. Therefore, R2 must return to their last legally occupied base, which is second base, before the interference occurred.

This approach helps to uphold the integrity of the game, allowing for the correct application of the rules of play, rather than rewarding the runner for an unintended consequence of the umpire's actions.