He started with talking smack and offered to prove his point. He walked away stunned, feeling he needed to rethink his approach. He said he was pretty experienced, but everyone says that to Brian before they get introduced to the ground.
Heel down allows you to engage the spine in developing power. This is a distinct skill that I have only found in CMA. Actually, there IS a bunch of stuff in CMA that just does not exist in the West. but most CMA guys don't realize what is IN Western MA. (Somehow Muay Thai gets clasified this way - but it's not - it is good silat stripped down for sport combat. So no surprise on shared principles.)