Double Steal with Inteference
With no outs and runners on second base (R2) and first base (R1), both runners are stealing on the pitch. The batter (B1) hits a ground ball to the third baseman. Just as the third baseman is fielding the ball, R2 collides into the third baseman. The third baseman was contacted pretty hard (but not maliciously) by R2 but he is still able to tag R2 and throw to first base. B1 just beats the throw and is safe at first base. R1 advanced safely to second base on this play.
The offensive coach insists that the third baseman was in the base path and R2's contact was unavoidable. The offensive coach also adds that this could not be interference -- since the third baseman was able to tag R2 and complete the throw to 1st base and nearly retire the batter. Meanwhile, the defensive coach thinks there should be more penalties than just the result of the play (which were: R2 out, R1 safe at second base, B1 safe at first base).
What do the umpires do now?