Saleen did not use the Crystal Finger. Although he was definitely able to use the skill anytime, his level was simply too low and the magic chords consumed by the skill would have allowed him to use over a dozen other level-11 magic spells.
He still had to deal with the other mages who had escaped after he was done with the purple-robed mage. There were nine level-11 mages in the Elemental Hand, and every single one of them had unnervingly ample combat experience. All would have caused him trouble in the future if they were allowed to escape.
With Saleen having taken the Baldur's Gate and Alchemy City by the skeletal dragon, there was no way those mages would have simply let the matter slide.
Saleen had to get the fight over with as quickly as possible.
