OBS or nothing

[Bluefoot]

Maybe this covers it:

POE: Over-Running First Base
"If a play is made at first base, but the ball is overthrown or the fielder is pulled off the base by an errant or missed throw, this also allows the batter-runner to use the white if trying to advance to second base."

F3's play to catch the ('errant') throw and tag 1B is what caused him to miss the white portion. BR touched the white portion, but was not trying to go to 2B.