This is the first pattern put into practice from the "Ambled" variations which does not have an equivalent pattern in the 27 Scrambled variations. This happens because when moving from the 9‑club base pattern to the 10-club base pattern, an extra beat with an extra pass is added, creating quite a few new "intercept, carry, substitute" combinations.
The first pass thrown by B (beat 2, marked blue in the video) is substituted and should be thrown as a tomahawk (an "ambled chop"). This pass is also a magic club – in the next round be the same club is thrown as a tomahawk again. In fact, the only throws with this club are the tomahawk and a zip. Try replacing it with some other prop 🙂