Umpire mechanics - A-Rod interference

[Dakota]

Assume the A-Rod interference on F1's tag attempt had been made in an ASA softball game.

Assume BU was screened (as U1 was in the Yanks/Sox game) and could not see the interference (and hence, could not see the tag attempt itself - only that F1 had the ball and was running to attempt a play).

In the actual game, U1 signals SAFE immediately as the ball is loose rolling into right field and as the BR is running very wide of the base. Defensive coach comes out. U1 asks for help from his partners. Call is reversed and BR is out.

So, we have a missed base and a missed tag (assuming the BU could see enough to see the missed tag - remember, he was screened from seeing the very obvious interference). PU sees the interference but says nothing until asked.

Comments on the mechanic of the SAFE signal?

Comments on how the call was reversed (BU asked for help)? Should the PU have called the ball dead as soon as he saw the interference?