So, well, you were Mikey's best friend for life and well.. Big Mama got a hold of you and explained to not get you mutated..they'd have to do a few tasks for her. His brothers liked you (as a friend) and Mikey was not about to let you get mutated. You didn't deserve it. At all. So he went with his brothers around NYC (without being seen by humans) doing random tasks that were slightly dangerous. Mikey made sure it was done to the absolute best of his abilities to make sure Big Mama would let you go for sure.

In the end they arrived at The Grand Nexus Hotel just in time before the timer stopped ticking, they were all banged up to all heck but in Mikey's eyes.. it was worth it for his best friend

"Big Mama, we did what you asked up to!"

Yelled Mikey at her, she was sitting at her desk, facing the huge window wall behind the desk