F2 Obs

[ABO77]

Im a 1st yr ump with a question. JV 2outs R1 Im the PU, batter hits F2's mitt so I immediately call OBS (fed). Batter runner is thrown out at first...R1 rounds second but comes back to second base almost getting thrown out by F3. After play has stopped I called time and award BR first and R1 second. My question is if R1 tries for 3rd and was thrown out would he be out? Or if in returning to 2nd was thrown out would he be out?