Which secret did Morris share with McMurdo? What solution did McMurdo offer him?

Morris told McMurdo that he wished to leave the order, but he was afraid for himself and his children.

I started a drygoods store on Market Square, and I prospered well. The word had gone round that I was a Freeman, and I was forced to join the local lodge, same as you did last night. I've the badge of shame on my forearm and something worse branded on my heart. I found that I was under the orders of a black villain and caught in a meshwork of crime. What could I do? Every word I said to make things better was taken as treason, same as it was last night. I can't get away; for all I have in the world is in my store. If I leave the society, I know well that it means murder to me, and God knows what to my wife and children. Oh, man, it is awful—awful!” He put his hands to his face, and his body shook with convulsive sobs.