I can't pretend to be a chef, which I'm not by any means. So don't take anything I say as an absolute. But, by leaving the meat in for such a short period of time, the outer layer will start to cook, ever so slightly. I wouldn't suggest leaving it in long enough to cook the meat right through though. Cook on other sources of heat. I've not had a problem with tenderness.

It's a trick that TR Michals taught me. And if I remember right, my Grandmother used to do the same thing with beef.