This combo consistently works if the opponent keeps tech rolling to the left. It's still doable if they tech roll right, but the route needs to be adjusted. Of course they can stay on the ground and avoid it entirely.
Also Reina Top 1 character
Here's some unique combos you can do with heihachi only with warrior instnct.
The first two of course aren't optimal for damage, but it's a way to do the activation mid combo.
The second one also removes the grey health that was created from the first half of the combo, which is something that you can only really do with this type of combo.
The third one does only work if you do a cd1 with no electric input, because it gives you more frames.