The downfall of Qui-Gon comes from having to fight Darth Maul alone. Why didn’t Qui-Gon wait for Obi-Wan?
Qui-Gon didn’t wait for Obi-Wan because Darth Maul requires too much attention. Obi-Wan is knocked onto a lower walkway that’s far from Qui-Gon, and the Jedi Master can’t afford to turn his back on Maul.
He is able to put Maul on the defensive, pushing him into a far-away room. Obi-Wan uses a Force Jump to reach the duo’s level, but he’s too far away to join the fight in time.
Darth Maul enters the fray
In Star Wars: Episode I – The Phantom Menace, Obi-Wan and Qui-Gon face off against Darth Maul as a duo for the first and only time. A group, led by Senator Padme, aims to capture the Viceroy and cause confusion within the Federation army. It is the same Viceroy that tries to end Qui-Gon and Obi-Wan with poisonous gas.
Once Darth Maul appears, Qui-Gon informs the group that he and Obi-Wan will handle it. Senator Padme and her group take the long way around, allowing space for the soon-to-come lightsaber battle.
At first, Qui-Gon and Obi-Wan are able to team up against Darth Maul. Each Jedi takes a different side, but Darth Maul is able to lead the Knights into a larger room that’s suspended many miles into the air.
The room, revealed to be a large power generator, contains different walkways that are separated by many feet of distance. The group fight each other on a high-up walkway before Obi-Wan is kicked by Maul on to a lower walkway.
Qui-Gon faces Darth Maul, decides not to wait for Obi-Wan
Quickly, Qui-Gon knocks Darth Maul down onto the walkway above the one that Obi-Wan dangles from. By the time Obi-Wan pulls himself up and does a Force Jump to the same level as Qui-Gon and Maul, the two have fought their way into a side room.
Looking to keep the aggressive strikes flowing, Qui-Gon does not want to wait for Obi-Wan to catch up. The Padawan is many feet away, and waiting for Obi-Wan before continuing the fight would be impossible.
Qui-Gon pushes Maul back into a hallway of rooms that “lockdown” for certain periods of time. This lockdown separates Obi-Wan, who is in the room closest to the entrance, from Qui-Gon and Darth Maul in the two furthest rooms.
So that’s the answer. Qui-Gon didn’t wait for Obi-Wan because fighting Darth Maul requires too much attention. Obi-Wan is knocked on to a lower walkway, and Qui-Gon keeps the pressure against Maul on.