Flow In Groundfighting

You fellow Dojo Rats out there know that I'm a nut for flow drills. Give-and-take, a little rough, but at a pace where skills become drilled into our "reptile brain". I am also adverse to over-reliance on groundfighting, especially in a hostile or group environment, but we have to prepare for the possibility as many fights end up on the ground.
With that said, here's a great example of "flow" in groundfighting. Nice pace, nobody attempts a submission, lots to experiance and learn in a generally injury-free session.
In the heat of the "Bus Station Jujitsu" video, I thought we'd look at a little grappling.