Yep. Sark is a 180 degree turn from TH. He's definitely passionate about coaching. But he's also very disciplined and professional. He's not going to lose control, and certainly not in public. He appears to be a man who has been through the wringer, in the most public way possible, and came out the other side a better/stronger human being.
This is a vital component of his hiring. The old adage of "as above so below, as within so without" is quite true. If a person can battle and defeat their own demons, chances are they can help do the same for other people. And organizations. And that's exactly what I expect Coach is going to do here.