The Marcionite Gospel was Secret Mark

I haven't done attempted to demonstrate that 'secret Mark' was one and the same with the Marcionite gospel in some time but consider this strange tidbit from De Recta in Deum Fide.  The Catholic representative (Adamantius) uses the resurrection of Lazarus as an example demonstrating Jesus's ignorance.  The text has the Marcionite (Megethius) declare this particular statement - i.e. 'where have you laid him?' - doesn't appear in the Marcionite gospel.  So it is that Adamantius choosing another passage.  But clearly Adamantius thinks that the Marcionite gospel (a) contained a reference to the raising of Lazarus but that it differed with respect to Jesus's ignorance:

MEG. The Creator God did not know where Adam was, when He asked, "Where are you"? Christ, however, knew even men's thoughts.

AD. How is it then that Christ said concerning Lazarus, "Where have you laid him?" Perhaps He was ignorant where he lay!

MEG. This is not written in our Gospel.

AD. You know that you undertook to make your proof from our Gospel, d But since you do not want this, what is meant when Christ inquired from the chief of the demons, "What is your name?" and he replied, "Legion"? So according to your Gospel He was ignorant, and therefore asked the question. [De Recta in Deum Fide 17]

Now compare Secret Mark where Jesus knows where the tomb of the youth is:

And, coming, she prostrated herself before Jesus and says to him, 'Son of David, have mercy on me.' But the disciples rebuked her. And Jesus, being angered, went off with her into the garden where the tomb was, and straightway a great cry was heard from the tomb. And going near, Jesus rolled away the stone from the door of the tomb.

and compare that with the reference in John where Jesus displays his ignorance about where the body is located:

When Mary reached the place where Jesus was and saw him, she fell at his feet and said, “Lord, if you had been here, my brother would not have died.” When Jesus saw her weeping, and the Jews who had come along with her also weeping, he was deeply moved in spirit and troubled. “Where have you laid him?” he asked. “Come and see, Lord,” they replied. Jesus wept. Then the Jews said, “See how he loved him!” But some of them said, “Could not he who opened the eyes of the blind man have kept this man from dying?” Jesus, once more deeply moved, came to the tomb. It was a cave with a stone laid across the entrance. “Take away the stone,” he said.