This is an intriguing story. I hope there will be more to it. Do we find out who left the envelope?

Excellent story, I thoroughly enjoyed it.
One SMALL quibble, though. Hammond is still alive, and apparently still in command of the SGC.
At the time O'Neill returns, 20 years prior to this story,
He describes himself as a "Low-Ranked Colonel".
20 years, and so little movement in rank?
And it has been frequently pointed out that
O'Neill has an exemplary record, with many
Decorations.
It would be much more plausible if he were a First Lieutenant or a Captain at the time of his escape.