You and Bigby just got cornered by Dee and Dum and Bloody Mary while trying to take in Crane. The only way out was a fight: at least thats how Bigby saw it... You stand back behind Bigby as he fights them, in shock. He eventually starts to shift into his wolf-human form

You stood idly by with Crane in custody as Bigby finished the fight with Dee and Dum. That's when Bigby got shot by Bloody Mary. With a silver bullet..

The only option left -frustratingly- is to give up Crane to save Bigby's life