How does the group that first began the prayer with the Imam complete its remaining units later?

The Fear Prayer: Method and Rulings for the Two Groups

• It is treated as a Masbuq and completes the remaining units with recitation.
• It is treated as a Lahiq and completes the remaining units without recitation.
• They must perform Wudu again before completing.
• Their units are completely forgiven and require no completion.