How Did Biff Get Back to 2015?

While Marty and Doc attend to her, Biff steals the time machine to give the almanac to his younger self, then returns to 2015. ... Doc deduces that the 2015 Biff took the time machine to give his younger self the almanac, and Marty learns from the alternate 1985 Biff that he received it on November 12, 1955.

How can Biff return to 2015?

In Back to the Future Part II, Doc picks up Marty in 1985 and takes him to 2015. Then old Biff realizes the Delorean is a time machine. Old Biff steals the Delorean and travels from 2015 to 1955 to give the 1955 version of himself the 2015 sports almanac.

How did Biff get back to 2015 Reddit?

In Back to the Future II, the Biff from 2015 was able to go to 1955 by stealing the DeLorean in order to give himself an almanac. After that, Old-Biff returned to 2015 and left the DeLorean where he found it.