Dating What Daddy Hates: While Brainwashed and Crazy, Tang Shen claims that the reason why she poisoned April and Casey was because they aren't good enough for Donnie and Miwa and that it'd be better if they died before they "[dragged them] all down".
The Door Slams You: When Mikey lets a frantic Kirby in, the moment Mikey turns the knob he gets smashed into the wall.
Fighting from the Inside: When Tang Shen poisons April and Casey while under Shredder's control, it is not until after they are cured does Donatello find out that her venom is only lethal with several bites and that April and Casey would have been fine after a few hours. They take this as a sign that there is a part of her still holding back from the brainworm's influence. The fact that the snakes in her hair try to bite the Shredder despite being brainwashed probably helps.
For Want Of A Nail: While in "The Deadly Venom", Leo and Donnie get poisoned by sewer water saturated with Karai's venom. Here, all of Tang Shen's sons end up paralyzed with a numbing agent instead.
Good Parents: Kirby recognizes that in-spite of all of the danger that comes with his daughter associating with the Hamato Clan, their self-defense classes and willingness to protect her far outweigh such concerns.
I Lied: Tang Shen manages to convince all of her children to come out of hiding by promising the antidote to her venom to save April and Casey with. By the time they got there, they had been drugged with a numbing agent, whereupon she admits she lied about having an antidote.
Like Father, Like Son: During the battle between Leo and Tang Shen, they both bring up points how much he is like his father.
Parental Sexuality Squick: Mikey finds the idea of Tang Shen being in any way romantic with the Shredder as "a gazillion times more gross than that sewer water was."
Poisoned Weapons: Tang Shen manages to poison Casey with an arrow laced with her venom.
Poisonous Person: Tang Shen's venom, while not lethal in lighter doses, is fast-acting, highly-potent and can even seep straight through the skin. While brainwashed, Tang Shen expects Donnie to make an antidote not to save April and Casey, but so that she could be intimate with Shredder without killing him by accident.
Pragmatic Adaptation: The race that happened in "Meet Mondo Gecko" is glossed over as just a thing Casey, Mikey and Jason had endured "just the other day."
Pyrrhic Victory: Casey has grown to see them stopping the Kraang as this, since the Foot Clan's activities have denied everyone any time to celebrate.
Casey: It's just things were supposed to be getting better! We beat the Kraang, we took back New York, we all had our families again. And even with all that... We won. So why does it seem like our friends keep losing? April: Because the Shredder is awful. Casey: Understatement, Red.
Sanity Strengthening: Using DNA samples he collected from Leo (post-mutation and demutation), Buzzkill was able to restore Tang Shen's mind to its original self.
Suspiciously Specific Denial: When Irma asks why the Hamatos aren't back at school like the rest of them, Casey responds by denying knowing anyone named "Hamato", resulting in a Facepalm from April.
Casey: That was way too close. April: Well, you sure were no help, Mr. 'Who-are-these-Hamatos'.
