When April is going over the footage to find out she really knew the turtles and Splinter, she tears up when she sees her father.
The destruction of the Lair, Splinter's temporary death, and Leo, Donnie and Mikey being carted away all the while Leo tells his brothers to stand strong.
The Turtles being forced to drop their weapons when Shredder threatens to kill Splinter.
Raph's speech.
"I just uh… uh, if this is our last moment together, I just want you guys to know I’m sorry. I’m sorry I was so hard on you. Uh… every time I pushed you, I — I threatened you, I yelled at you, I pushed you beyond your limits is because I believe in you. I believe in each one of you! I believe in your spirit and your intelligence and your potential. And every time I talked about walking away it was because I was scared — I just didn’t think I was good enough to stand next to you and call you brothers and say to you —- I LOVE YOU! …I LOVE YOU GUYS SO MUCH!"
Splinter cutting off his sons so that he can fight Shredder on his own, only to get the tides turned against him while Leo, Donnie and Mikey are forced to watch as their teacher/father is beaten to an inch of his life.
When April desperately tries to revive the turtles by pumping them full of adrenaline and they show no sighs of recovery, this enough causes her to scream out to them "GET UP!!!!" since the turtles are so close to death due to their blood being drained from their bodies.
And Raphael lying on the floor motionless in defeat from the Shredder having his shell almost completely cracked doesn't help either.
After Raphael survives from his temporary death, he enters the lair looking for any Foot enemies to battle and his game face immediately changes to worry the minute he sees Splinter lying amongst the rumble.
Raphael: Sensei! (breathlessly) Master... (helps him up) Let's get him to the needle room!
Raphael desperately trying to save his father but he can do is look on and worry what's going to happen next. You'll notice he's tearing up.
Splinter:(hoarsely) Ra-Raphael...?
Raphael: I'm here...
Splinter: You must save out brothers...stop Shredder.
Splinter's words to Raphael moments before he passes out
Splinter: Go Raphael.
When Eric Sacks firsts greets April at his meeting and talks about his working with her father and how proud her father would've been of her, she is clearly becoming emotional in their discussion and trying not to tear up in public.
When April learns the truth about her father: he was killed by Eric Sacks, someone she admired.
Eric Sacks: This is history repeating itself. Your father walked in on me, April! Just like you did! It took a few less bullets to take him down, though.
