I do not see a fielders choice as an option at 3rd when the only base runner was on second. Let me pose the question a different way.
No runners on any base with 1 out the batter hits ball to 3rd basemen who runs to third and steps on the bag no throw to first. Clearly this would be a mental error brain fart. When coach asked she says I thought there was a force play at 3rd.
How would you score this?
FC Fielder chose to run to third. A routine play would have had the batter out at 1st.