Before you drop the thread, please let me answer the hypothetical. As I understand it, I die and wake up before Allah who gives me the choice to accept him or go to hell. I may or may not be dreaming.
Well, yes, but I just added the "dreaming" part because some people were having trouble going with the hypothesis.
If I am dreaming and accept Allah in my dream and wake up and find it is not true, I'm sure that God would forgive me. After all, I've committed murder in my dreams before. (TMI?

) So, I would have to say that I would probably accept Allah in my dream, even if that meant admitting that perhaps Christianity was wrong about Jesus.
If it were really happening, I would do the same thing. After all, muslims and Christians worship the same God. One of us will find out in the end who had it right.
A very enlightened approach.
Just to be on the faecetious side of things, though, I would point out that muslims believe that everybody will eventually go to paradise, even the devil, after they have served their time in hell. So, any Christians who wanted to defy Allah would be safe in the end. They would just experience extreme discomfort for a period of time.