Castle/Recap/S4 E7 Cops and Robbers

At a tedious meeting with his bank manager to secure a loan to renovate Martha's acting school, Castle excuses himself to call Beckett in order to distract himself -- only to end up directly reporting the bank heist that kicks off moments after to her. While Castle, who ends up held hostage in the bank along with everyone else, tries to figure out precisely what the robbers are after, Beckett ends up being roped into the role of hostage negotiator after the lead robber, having interrupted Castle's call to her, takes a shine to her. It soon becomes apparent that the robbers are more interested in the contents of a particular safety deposit box more than anything else -- which is complicated by the fact that it's owner has just been murdered...

Tropes:
"Trapper John: Now you got one minute, Kate!
 * Audio Erotica: Trapper John has this opinion of Beckett's 'bedroom voice'.
 * Bank Robbery
 * Call Back:
 * The Old Haunt, the bar Castle bought in "Last Call", is mentioned again.
 * Castle alludes to several of the times he has saved Beckett's life over the course of the series.
 * Continuity Nod: Castle is apparently keeping score of precisely how many times he and Beckett have saved each other's lives. By his count, he's ahead. Beckett is less-than-impressed either way.
 * Everyone Can See It: Trapper John is quick to sense something between Beckett and Castle, and often refers to Beckett as Castle's 'girlfriend'. In a curious inversion of how the series normally plays this, it's Castle who denies the relationship, while Beckett does nothing to dissuade this belief.
 * Everyone Knows Morse: Castle uses a mirror to communicate with the police outside the bank in Morse code.
 * Genre Savvy: Relax, Castle knows what to do in a hostage situation. He's seen Die Hard.
 * It's Personal:
 * Ryan and Esposito are slow to react to the report of the bank robbery... until they learn Castle's inside the bank in question, at which point they immediately kick into action.
 * Beckett herself is clearly not going to be very happy with Trapper John should any harm befall Castle:

Kate: No, I've got twenty. You hear me? Twenty. Because if you pull that trigger I will personally walk through those doors and put a bullet through your skull."


 * Jurisdiction Friction: The S.W.A.T team leader is quick to shoot down any idea that Kate might have of getting involved in proceedings... until it turns out that Kate is the only one Trapper John will talk to. This creates a bit of tension between the two.
 * Long-Distance Relationship:
 * Mama Bear: When it looks like one of the bank robbers is going to shoot Castle as an example, Martha has to be held back to prevent her from attacking Trapper John.
 * Moment Killer: When the bank is stormed and the hostages released, Beckett and Castle are clearly having a very romantically charged moment... so romantically charged, in fact, that Martha has to remind Beckett that he isn't the only person in the room. Castle, like much of the audience at that point, is clearly thinking "Goddamnit Martha!"
 * Pregnant Hostage: One of the bank tellers is heavily pregnant. Subverted, however, in that she doesn't enter labour or really have that much effect on proceedings; Castle uses getting her a pillow as an reason to try to get to a window and thus try and send a message to the police,  but that's pretty much the most effect she has on the plot.
 * Secret Keeper:
 * She Is Not My Girlfriend: Castle's response to Trapper John's suggestions about his and Beckett's relationship.
 * Shout-Out:
 * The bank robbers use the names of fictional TV doctors as aliases -- Trapper John, Dr. Huxtable, Dr. Howser and Dr. Quinn. Doctors House, Shepard and Phil also get name-checks.
 * Castle, being in a hostage situation, naturally takes the opportunity to cite Die Hard.
 * Wounded Gazelle Gambit:
 * You Have Outlived Your Usefulness: