BIZARRE Play - Abandonment?

[Ump K]

Had a BIZARRE play happen in a game this weekend that made me wonder what is the correct ruling is if something similar to this play would happen again.


Situation;

R1 & R2, no outs. BR bunts the ball in the air in front of the plate F2 dives for the ball.

PU sees the ball wasn't caught and signals fair ball. F1 throws the ball to F6 at 3B, R2 is safe at 3B.

BR is safe at 1B, however coach thinks it is foul ball and sends BR back to the plate.

F6 throws to F1 who tags BR out between 1B & HP. Case closed no problem for us.


However;

Should've we called BR out when she started back to HP AFTER she was SAFE at 1B?
BR was legally safe at 1B. What if she got into a run-down between 1B & HP. Would she be out if she would retreat to HP?