The Gospel of Peter - Is Mark Using Mark as His Primary Source?

It can seem open and shut for matthew to be using luke as a source, like ou mentioned in the show. But it would still argue that luke could have written post matthew with two things. Luke having the various teachings out of order might be him rearranging them chronologically. Mark records peter's sermon notes, not chronological. Matthew fleshed out of order mark to tell people to listen to this gentile accommodating peter from the council of jerusalem. And then luke gives the account in order chronologically. It does make it a little less open and shut about the order.