As if stressing out about moving in with her boyfriend wasn't enough for Avery to worry about, Nox had been getting attention on the news. Everyone was speculating about the "new hero" who saved Mercury and wondering why he hadn't made another appearance since then.
Everyone was wondering what happened to Mercury too. Christian hadn't come forward to make any statements about his retirement but he was obviously serious about it since he wanted her to move in.
Knowing him, he was more the type to want to fade into obscurity than go out with a lot of fanfare. He probably thought his job was done so there was no reason to keep pushing himself and possibly wind up dead. After all, he wasn't getting any younger.
Things were different for Avery. She had a mission she had to fulfil. One that couldn't be taken on by the next new hero who showed up.