While checking the motives of possible suspects, Beckett and Castle pay a visit to the captain of the oil tanker who survived the blast. Capt. Pike is covered with burn scars and confined to a wheel chair. Clearly, an homage to Capt. Christopher Pike from Star Trek T.O.S.
When Castle challenges Beckett to a final cards showdown, he says "mano a mujere." Beckett calls him on it as the wrong expression "hand to woman." She is correct. The correct expression would have been "hombre a mujere."
This episode aired the day after Stana Katic's 31st birthday. Beckett wouldn't be acknowledged as being 31 until "Rise (2011)".