Awesomeness by Analysis: Slash was able to undo Leatherhead's paralysis himself, having learned it after observing it as a regular turtle.
Slash: Living with ninjas all your life can be very informative. I saw Master Yoshi do that sort of thing I don't know how many times.
Cursed with Awesome: Donnie surmises that while the wound Shredder gave Leo would have been fatal, his mutation was able to heal most of it as he mutated.
Leo's fight with the Foot Clan resulted in him being thrown through the window of April's home after being beaten and battered at the hands of the Shredder, leaving him out of the fight. Here, Leo's unconscious state is due to the combination of mutating into a mutant turtle, the shock of being stabbed by the Shredder and the cold, resorting to his body shutting down to the turtle's basic instinct in response to cold: hibernation.
Instead of using the Turtle Mech against Kraang Prime (for Donnie hasn't been able to get it anywhere near completed, let alone get a power source for it due to not having visited Dimension X yet), the Hamatos, April and Casey turn the tables on him at a gas station.
Ho Chan sensed the missed opportunity to escape he would have had in canon, if the Kraang invasion hadn't happened that day. And muses that "maybe he would be set free next millennium."
History Repeats: Much like that faithful night 15 years prior, Shen moves to block a killing blow meant for Yoshi by Saki. In this case, it was a non-lethal blow that ends up shoving both of them into a whirlpool.
For the two ninja masters, it was the fight from fifteen years ago all over again. Shredder attacking, Yoshi injured, and Shen between them ready to take the blow in her husband's place. For an instant, it was as if time stood still for the three involved as it sank in that this was really happening again.
Missed Him by That Much: Casey and Raph arrive at the apartment building just after Slash and Leatherhead got Casey's family out to safety.
My God, What Have I Done?: After accidentally sending both Tang Shen and Yoshi into the whirlpool, he briefly collapses at the thought that he had more or less killed Tang Shen all over again.
The Shredder glance back at her blankly, before turning and walking away, hunched over in pain from the injuries he'd received, and the realization that he had lost the woman he loved once again.
Pet Dress-Up: When Slash and Leatherhead try getting Casey's family to safety when the Kraang invade, they are naturally terrified of these two gigantic mutants at their doorstep. When Slash tries convincing him that he is friendly, both of them knowing about Raph's pet turtle Spike, Slash reluctantly recalls a time when Casey's younger sister Shadow put him in a dress and called him "Princess Spiky". It is especially embarrassing for him because Leatherhead is standing there off to the side, respectfully quiet but otherwise amused.
You Can't Go Home Again: The Hamatos, April and Casey are forced to get out of the city. The very fact that Raph of all people, is saying it, hits them hard.
Raph: "The Kraang have invaded, Donnie's Turtle Mech isn't anywhere near finished, and we are two down, and completely outnumbered," said Raph, looking more defeated with each word he uttered. "No matter how you look at it, this isn't a fight we can win, so we have to get out of the city".
