Essenla paused. Anyone with half a brain could tell that it wasn't her inability to control the fire that made her reluctant, but rather what the flames would do.
Burning to death was a horrible way to go. She didn't want to inflict that on the Dryad, who was only defending her home. She'd rather make it clean and painless, but it was clear to her that was no longer an option.
They couldn't get through this dome any other way, and they couldn't leave the Dryad. If she left the protection of her dome, she could wreak havoc on the goblins before Morne and Essenla managed to make it back to her.
None of the goblins present had the eight mushrooms required to absorb the Chimh of a Mage's Spells. They had only their telekinesis, and the battlefield was too hectic to use that safely. Using it carried the risk of hurting their fellow goblins, so they had to use it sparingly.