It was a pre-destination paradox. The whole thing is a cycle and it doesn't really have a starting point. SG1 couldn't have waited 30 odd years to tell Cassie to wait for them in the future because they never made it to the future in the first place.
In the end it's just a cycle that keeps on going in a never ending loop.
In the end it's just a cycle that keeps on going in a never ending loop.
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