Final answer:
When a group drift dive separates, students should have a predetermined plan to follow when they lose sight of the group.
Step-by-step explanation:
When the student and his buddy stopped to take a photo during their group drift dive, the group appeared to have drifted around a corner when they looked up.
To catch up, they swam a little faster but couldn't find the group after rounding the corner, even with good visibility.
Unless planned otherwise, in such situations, they should have a predetermined plan to follow when they lose sight of the group.
This plan should include procedures for regrouping or returning to a predetermined location.