Buying time with distractions- now that's something The Doctor typically excels at.

"How would you like to be the next one set on fire Blanche? Luce and I have plenty of firepower saved just for you! In case you couldn't tell already a fire extinguisher won't do you much good once you start sparking."

He doesn't expect Blanche would be hit by a regular ol' fireball from music magic. Luce's flame is something new and unpredictable though; better to take a gamble on that. Doctor concentrates his efforts on the flame squirrels running across the floor and tries to conjure up the illusion of several more of them being created as if Luce was responsible.