These are the relevant TDA rules.
Quote:
13: Tabling Cards and Killing Winning Hand
A: Proper tabling is both 1) turning all cards face up on the table and 2) allowing the dealer and players to read the hand clearly. “All cards” means both hole cards in hold’em, all 4 hole cards in Omaha, all 7 cards in 7-stud, etc.
B: At showdown players must protect their hands while waiting for cards to be read (See also Rule 65). Players who don’t fully table all cards, then muck thinking they’ve won, do so at their own risk. If a hand is not 100% retrievable and identifiable and the TD rules it was not clearly read, the player has no claim to the pot. The TDs decision on whether a hand was sufficiently tabled is final.
C: Dealers cannot kill a properly tabled hand that was obviously the winner.
14: Live Cards at Showdown
Discarding non-tabled cards face down does not automatically kill them; players may change their minds and table cards that remain 100% identifiable and retrievable. Cards are killed by the dealer when pushed into the muck or otherwise rendered irretrievable and unidentifiable.
15: Showdown and Discarding Irregularities
A: If a player tables one card that would make a winning hand, the dealer should advise the player to table all cards. If the player refuses, the floor should be called.
13 a. he obviously violated that. hand is not properly tabled
b. he did not properly table the hand, yes. but the cards he did reveal were enough to win the hand so the floor might make a decision that they were sufficiently tabled to win the hand. however he might rule them not sufficiently tabled.
14. the two cards not in the muck are identifiable and thus clearly still live.
15. this one is weird. I would say this is more that he should have told the guy to table all cards in the first place. I think this is no longer applicable because the cards should be recovered first before they are tabled. so the dealer should call the floor over and let him make a decision.
think it becomes more interesting if the cards were not so obviously retrievable. just let the floor recover the cards and push the pot. hell even if he doesn’t recover the cards push him the pot and give him a warning that his hand will be declared dead next time if the cards are mucked by the dealer.