Because of varying episode numbering across different versions of the franchise, "Episode 101" can refer to different events:
Having been brought back to life by the wish made on Earth's Dragon Balls (to revive those killed by Frieza and his men), Vegeta briefly witnesses Goku's Super Saiyan form before being teleported to Earth.
Believing his father was dead, Gohan briefly returns to the fight to stall Frieza before being sent to Earth with the others.