[nopachunts]

I was watching a replay of the Louisiana 5A championship game last night. R2, U2 at 3B, U1 between 1B and 2B, not sure of outs, three man crew. Batter hits a fly about halfway between 3B and the foul pole right on the line. U3 is backing perpendicular to the foul line away from 3B. I couldn't see the PU to know what he was doing. The TV announcer sounded surprised went the runner's countinued to run as no one signaled fair/foul. Was U3 correct in what he did? What is the correct rotation in this situation?