but it was not a player who dropped card to the floor, but the dealer. Therefore a misdeal as per rules A and F
(a) The first or second card of the hand has been exposed by a dealer error.
This rule only applies to the first or second card dealt. So it wouldn't cover it if it was say the 3rd card dealt.
(f) Any card has been dealt out of the proper sequence (except an exposed card may be replaced by the burncard).
And this means dealing to players in the wrong order. I don't think we apply this here.