I must be misremembering the order of things in Reckoning/Threads. I thought for sure that it was Selmak who was dying, but Jacob kept Selmak around long enough for him to finish his work defeating the Replicators/Go'a'uld. EDIT: Wikipedia, the cardinal source of all knowledge(tm), confirms my memory:
Yeah, Selmak was dying. He could have left Jacob weeks earlier and saved Jacob's life, but he stuck around to help with the work. By that time, it was too late for Selmak to leave Jacob, and so they both died.
Exactly. The reason Jacob is dead is because the symbiote died inside of him and released the toxins.
Weak. I am sick of the Goul'd (most especially Baal), tired of time travel (which isn't Stargate's fault) and was just hoping for something more...
I thought it was OK, but truth be told, I liked Ark of Truth better. Reset Button episodes always have that "so what?" quality to them that just leave me feeling very....unaffected.