>left backfist and slide right hand
Told you, the only move is a back first with the left. This only works because it is choreograph fighting, and only with that in mind "5. there is no step 5".
Like I said earlier, in this pic at that point his wing chung right hand is still not in control of the opponents right arm. Take this test. Drop a crisp dollar bill 1 inch above someone waiting to catch it with two fingers. See if they can catch it, grasshopper. You must be able to move within a "flash" time frame least your opponent interprets. Any questions?