|3-3-6e1: In inversions where the base of support begins at or passes through prep level:… (this begins at prep level)
1. At least two people … must be in a positions to protect…
Since this skill starts at prep level and goes inverted, it needs two on the upper body, in a position to protect the head, neck, shoulders.
If it dropped down to waist level first, then went forward, it would require one person in that position.