Obstruction, Look Back--NFHS

[jmkupka]

RKB, that is the play I'm questioning:

Ordinary single to F9. BR rounds 1B and is obstructed. Returns to 1B and stands on it.

Ball is relayed from F9 to F5 to F1 (in the circle).

BR takes off for 2B:
1. after F5's relay, but before ball is caught by F1.
2. after ball is caught by F1.

In either case. BR is tagged out at 2B.

In 1, BR is still protected, and returned to 1B, because both elements of the exception are not met.
In 2, is it not a LBR violation? And if not, how long does F1 have to have possession before it is?

We don't call time and award the base (if she's on the awarded base), so what else ends the play?