Even after the dissolution of the countless nations of Humanity into the Akashic Pillar, and the creation of it's current system, it was amazingly easy to get lost in the system. And subsequently, be labeled as dead. The fact that Sega had been dead was besides the point, because the stop gap in place to allow those people that had been labeled as dead to clear up their status made it easy for Sega to reinstate her everything.
The downside though, was that this meant a lot of paperwork. A whole lot of paperwork.
Your big sister had spent the four days you were on vacation running appointments and stacks of paperwork around. She was lucky that Firebase Momo had nearly every department she had to interact with in order to pull this off. For the few places she had to go that weren't on base, Rei had packed Sega and San both up and drove them to where they needed to go. Then used that chance to pamper her sister and get to know your sister at the same time.
The problem with this though was Rei, being Rei, told absolutely no one that she was leaving base with the recovered girls. And while you could almost hear Commander Mason's teeth grinding from across the base, you also found out what frustration in Sega felt like. It was very surreal.
"So... Rei took Sega and San... what?"
"Goddess Gold took Goddess White and Solid Drive both a few miles down the road to celebrate Solid Drive's reinstatement as a citizen of the Akashic Pillar. I heard they went to a club called 'Happy Cat' or something." You stare at the guard in disbelief for a moment.
"... But isn't Sega under age?"
"No actually. The drinking age for this region is 19 instead of 21 like it used to be."
"I'm going to have a drunk sister when they get back... Who did I piss off in a previous life to deserve this?" You had the misfortune to experience a drunk Sega one before in your life. One Christmas she had gorged herself on eggnog and gotten tipsy.
"I need to find a fallout bunker or something." Never again if you could help it. Sega without her inhibitions was a truly frightening thing, what with the fact you were pretty much her sole motivation in the world. You didn't need death threats getting mailed across half the continent again.