Wisely, Mitch bit down on his tongue just this time, though this caused his would-be response to be a slightly muffled, "Erhm..."
When he had offered to help Blythe, he did expect that his "power" would factor in somehow. Otherwise, she could have called upon just about anybody else with just normal human capabilities... or with other "super"-human abilities. So he just figured that his fire was why she requested his presence. That didn't mean Mitch was eager to throw fireballs at anybody, of course.
It was nice to know that what he could do was a part of his lifeforce, though. That was pretty neat.
He decided to listen for Blythe's response or Alessa's input before butting in his own opinion of the situation.