Situation: 2 outs, runner on 3rd. BU is in position C. Ball is hit to F5, R3 dives back to base under the tag attempt. F5 turns and throws to F3. PU is focused on making the call at 3rd. BU is also focused on the play at 3rd. Close play at 1st and BU admits did not see play. PU calls runner out. My understanding is in the 2 man setup when BU is in position C they are responsible for plays at 1st. Is that correct?