Complex sentence: This leads to a lightsaber duel between Obi-Wan and Vader, which ends when Vader loses his legs and left arm, and is significantly burned by one of the planet's lava flows.
Split into simpler sentences: This leads to a lightsaber duel between Obi-Wan and Vader. Vader eventually loses his legs and arm, and is significantly burned by one of the planet's lava flows.