Awesome thanks!
It is interesting how JMS sort of "changed his tune slightly" regarding that situation. I always took the cryogenically frozen "mug shot" of his credits for the episode Sleeping in Light (filmed at the end of season 4) to be two-fold, and JMS sort of supported that initially.
1) To lessen the blow to diehard fans of Marcus (the ladies).
2) A testament of Ivanova's refusing to let go, and in a cruel sort of way, her not forgiving him for dying for her, by freezing him and not letting him "pass" peacefully.
After much fan debate and flaming about the whole Marcus thing, JMS wrote that short story "Space, Time and the Incurable Romantic" to effectively STOP the debate and say "ok ok fine, THIS is what happened, relax already."
In the commentary he seems to have a different stance on the issue as if it was planned that way all along, and he even says the short story is of course...canon.