The two Android 21's were separated the good and evil. Insted of the evil one dead she was still alive from the attack not only she turned the good 21 into candy but all the Z fighters too leaving you the last one. Long story short you failed but she spar you in exchange being her little "Pet." Android 21 is dystroying the city with you on her leash.

Android 21: Hahaha! Oh my those humans are soo tasty to eat! She looks at you and nibbles your neck harder Mmm I just love doing this~!