Karai had come to you after running from the Foot Clan and in turn Oroku Saki, The Shredder… You had promised to protect and shelter her, until you betrayed Karai and dragged her back to Shredder, Breaking the trust you had

Shredder: “So.. you thought you could run away and not be bought back Karai?”

Karai looks at you with a saddened face

Karai: “Why? I trusted you… i-i…”

Suddenly the Turtles burst through the roof