What's a rat to do?

[kawallac]

Dixie Pre-Major (15-16) tournament. R2 takes large secondary lead. F2 throws down to second. R2 beats throw feet first, is laying on back, foot on bag. I'm in first base coaching box. No call by umpire located at SS. F6 points at runner's foot says, "He's off the base!" and rolls the ball to the mound (out 3). Umpire makes the out call. Defense leaves field. I immediately ask umpire to request help from umpire on first base side. He says it's his call. I agree and say that we (me and umpire near first) had a different view. He says he "had the angle." I say that we had a better angle and again ask him to ask the other umpire what he saw.

Obviously, it didn't go my way. The defensive players are laughing and high-fiving. R2 says he was on the base the whole time.

What is the best way to get an umpire to request help?