Mike was first seen in Shorpacked! in February 2005. Now, I know what you’re thinking–the timescale is one of the major arguments for Mike not having used the chamber, and Mike had about a year. But there’s only one chamber, and Walky was using it until November. That puts Mike at four months to come back.

But let’s say Mike’s method was faster. It puts his date of employment at March 2004 at the earliest.

The “Flashbacked!” arc pegs both Ethan and Amber’s employment at five years before August 2007, or sometime in 2003. So they each have a year on Mike.

Now, the arc doesn’t show anyone else working at the store in 2003 besides Galasso and some random dude. But it’s not unreasonable to think that maybe Rick was already there.

So, seniority goes: Galasso, Rick, Ethan, Amber, Mike, Robin, Reagan, Leslie, Jacob, Ken, Malaya, Jeshua. With the mom at register in there somewhere, if she still exists.