That is not good enough. You will have to provide a clip or something where the Turtles explicitly say that they had to kill Timothy. I am pretty sure nothing about killing anybody was mentioned there and the character's article merely says he is frozen and waiting to be cured.
Just saying it really did happen in the episode without providing quotes or citations is not proof at all.
It's hard to say he is in supsended animation, usually people who are cryogenically frozen problems as they might not regain consciouness. Considering he is just organs which can be frozen for a period of time.