Correct Mechanic on Unusual Play

[Far far away ..]

3 man system, I'm U1.

R1 on 1st. Batter hits to F6, who fumbles and then drops the ball and then makes a desperate attempt to flip the ball to F4 and drags him a couple of steps off 2B. F4 now has to turn and try and get back to 2nd base. What should have been a simple force (and probable double play) now becomes a foot race which R1 wins in a bang bang play.

So far so good!

Problem is the runner was busting such a gut to get there they over-ran the base and so are straight back in jeopardy of being tagged out.

Defence assume they got the out and so aren't doing much. Offensive coach twigs what's going on and roars at runner to get back on base - which they do safely.

So - to my question. Should I have given an emphatic safe call on the bang bang play despite the runner being back in jeopardy - or is my non-call enough to let everyone know that the play hasn't finished yet? By the way PU knew full well what was going on because he wasn't calling time while all this was going on.

After a visit from a the defensive coach, who was disappointed when I didn't ask U3 for help because "it was all in front of me coach and I'm happy with the call" I wondered if a quick safe call would have been the right thing to do or if I had it right.