Agartha isn't our dimension lol its the Vril-ya's home world. By the way does anybody remember in Call of the Dead in the starting area in the water near the iceberg there is a strange design. To me that resembles an actual Vril-ya person. but anyways, I agree shooter Samantha did go back in time, and I believe her dying on moon might have her goto agartha. If you guys remember when playing Tranzit the first diary entry has Maxis saying Samantha disappeared. To where? Origins? Probably, but how the hell did she go back in the time? The Casimir effect is known to cause time travel into the past. Maybe she used the mechanism? Maybe she used a gersch device to goto Agartha. Lol I also agree with the fact that personal history is never changed, but alternate timelines are created when you time travel. Similar to Dragonball Z when Trunks time travels lol it creates a different branch off of the original timeline. I don't think people "fade away" or disappear that's illogical what is making them disappear? lol. I also don't think after Buried Maxis caused Origins to happen because he doesn't know whats happening when Samantha talks to him during origins, if he time traveled he would know lol. I think the serious questions here are How did Samantha time travel because that's truly the missing link.
Other things to note. There is a wunderflizz machine in Der Riese, meaning the events in france could have happened, but were overrun by zombies. Thus giving another important question, Why are there statues of the O4 at the mound.
BTW type 115 into the coder in MOTD and 666 comes up, meaning the devil. Type in 935 (richtofen, maxis, samantha) and 777 comes up, which is the perfect number in the bible, meaning Samantha could be a God or they are destined for something else.
Too many questions my friends but we are on to something.