Complex sentence: Tiger Claw then tells Shredder to retreat with him or the whole lab will go down with him and that he won, though Shredder feels that he hasn't won with Karai as a mutant.
Split into simpler sentences: Tiger Claw then told his leader to retreat with him or the whole lab will go down with him. He told Shredder that he won, though Shredder feels that he hasn't won with Karai as a mutant.