Karai and Splinter in “Unfinished Business”

I'm sorry, Father. I'm glad Donatello's alright.

Now you see the kind of pain and suffering revenge causes.

I know. I thought I could end this by going after his operations. But it's too much of a risk to go after petty targets, just to spite him. I promise, I will no longer go after Shredder's operations. I'll go after Shredder himself.