Or just run an ouro arc from the aforementioned pillar in your base to unlock it. Blueside lowbies can hit 15, run the rescue the mystic from the circle flashback, mission teleport to it, finish, getting the spelunker badge for Atlas medallion, exit and get the nearby Perez pupil plaque also for Atlas medallion. Then use your newly awarded ouro portal to get out of there.
Redside doesn't get anything quite so convenient that early but most of the first set of flashbacks are quick to run just to get your portal.