Very nice! And I think it is a wonderful idea that the last challenge is not mastering the shield in every possible way. But that it is how John accepts "defeat" - that isn't defeat but the solution to the last trial.
Very nice voices for all four of them - and also your OC are interesting and nice people.
And a great way to explain the flames on the dagger and Sheppard's arm in the wallpaper! *g*

Thank you very much for this wonderful story!

And this was one of my favourite sentences: McKay had just about reached critical mass. "Yes, yes, they're grateful, we're grateful, everyone's grateful, it's a wonderful day, la la la. Sheppard! I need to talk to you for a minute please?"