All it takes is a Spark
The two competitors were brought into the biodome, once more it shifted. What started as neutral ground, quickly began to heat up. Rock rose, then lava flowed into the room. A simulation of the fields of Mustafar, or other molten planets.
High hills of obsidian and volcanic rock were what gave the two stable ground, with rivers of lava flowing between.
And yet again, the robotic voice echoed through the biodome.
<Round Two! Fight!>
All that was left was the sound of crackling rock. The two left alone.