Batter-Runner Interference on Bunt

The runner at 1st base (R1) is stealing on the pitch. The batter (B1) bunts the pitch down the 1st base line. The pitcher fields the fair bunt and throws towards 1st base in an attempt to retire B1. B1 has been running the entire way to 1st base completely out of the runner's lane. The pitcher's throw to 1st base hits B1 when he is a step away from first base.
 
The ball ricochets into foul territory, so R1 advances to 3rd base and B1 advances to 2nd base. Do the umpires have an actions?
 
Call
The batter-runner is out when he runs the last half of the distance to first base outside the three-foot running lane and he interferes while the ball is being thrown to first base (NF 8-4-1g). The ball is immediately dead, the batter-runner is out, and other runners return to their base occupied at the time of the pitch.
 
In the situation below, B1 is out and R1 returns to first base.