Beckett and Castle barricade themselves in the witnesses apartment while attackers try to break down the door. The attackers manage to break the door open with exception of the chain lock and the dresser that is wedged against door. The camera changes to the attackers point of view and you can see the attacker never actually make it into the apartment before they take off running. When Esposito gets to the apartment he pushes the door open you can clearly see the chain is intact but not attached to the door. When Esposito enters the apartment you can see the dresser is no longer wedged against the door and the apartment has been trashed. Since the attackers never entered the apartment the chain should have still been attached to door and dresser should have still been wedged against door. It should also be mentioned that since nobody entered the apartment and Beckett, Castle and the witness had already left there is no reason the apartment should have been trashed.
Becket breaks a parked car window to get a cellphone but then says that she cannot use it to call for help because it is password-protected. 911 call can be made without unlocking the phone on any phone sold today as a mandatory feature. Previously Becket pointed out to Castle that he doesn't need a dollar to call 911 from a payphone.
Actually there is a diamond mine in the United States. It is located at the Crater of Diamonds State Park Arkansas. It is the only diamond mine in the world where tourists can mine for diamonds.
Esposito "cocks" his pistol before he enters Leo's apartment. Glocks are striker-fired and don't have hammers.
The nun said that Father received a message while offering Mass, and left. Messages would not be delivered during Mass, and a priest is obliged to complete a Mass, once begun.
The nun's statement that the priest left in the middle of the Mass can be true. She never said he was the one delivering the Mass. There are usually more than one priest in large churches, and he could be just sitting in.
FCC rules require that any 911 call made on a cellphone will be routed by whatever network is available, regardless of whether the user is a subscriber. Windows phones, iPhones and Android phones all include an "emergency" option which enables the user to make emergency calls even on an otherwise locked phone. They could have used the "found" phone to call 911 even though it was locked.
When the team is examining the murder scene Lanie says of the killer, "He picked up all the spent shell casings." At this point, though, the team doesn't know whether Father McMurtry was shot with a semiautomatic pistol, which ejects spent casings, or with a revolver, which doesn't.
While hiding out in the playground, the witness, Leo, mentions that the C train is only six blocks from them but he lives in the Bronx, on 223rd street. The C train doesn't go to the Bronx.
(at around 12 mins) In response to Gates's instruction, Esposito says, "Ma'am." Yet Gates has been clear she wants to addressed as sir or Captain.
Beckett tries to send an SOS via the CB radio but she only ever sends OS (three long burst "dashes" followed by three short burst "dots").
Considering that he's personally met Joe Torre and appears to be familiar with his success, it can be inferred that Castle follows baseball to some degree, and shouldn't be as dismissive of the game as he is at dinner with his mother and the Becketts.
The second time Beckett is seen sending Morse code over the CB radio, she is not sending an SOS. She is actually sending the letters "i e o a u" (dot dot; dot; dash dash dash; dot dash; dot dot dash). She is interrupted as she begins sending the next character, which seems to start with a dot.