I don't play live but I'm surprised if this isn't at least an angle shoot. Reinkemeier calls, RDW shows enough of a hand to beat him, Reinkemeier should then muck, imo. It would help if I could make out what the players were saying to each other, or understand the interview, but by not mucking, Reinkemeier claims to be able to beat the K. RDW does himself no favours by not showing both obv, but Reinkemeier doesn't just know he's beaten, he has been
shown that he is beaten, and should muck. Reinkemeier is essentially claiming to be able to beat a hand that he cannot, simply by not mucking. So RDW mucks, or tries to.
e: By not mucking he is effectively declaring a hand that he does not have, surely?
But again, I don't play live, and should probably stfu.