What crisis does Stephen face in Book 2? Does it surprise you how he handles it? Why or why not?

A false key is found in the street and it is concluded that the safe was broken into with the false key. Bounderby immediately suspects Stephen Blackpool for not only has Stephen left town, but Mrs. Sparsit and Bitzer can testify to the man's ambling back and forth in front of the bank for several days before the robber took place. Stephen seems to have gone into hiding under an assumed name. This makes him look guilty.