In A Wrinkle in Time by Madeline L'engle, how is Meg impatient?

Meg reveals her impatience early in the novel when she tackles a boy from school who calls Charles Wallace "dumb" and gets a black eye as a result of her efforts. But it is on Camazotz that her impatience shows itself most fully. She doesn't want to linger when they arrive. She wants to get straight to her father and save him.
She is ready to jump out of her skin when she Charles Wallace and Calvin arrive at the Central Central Intelligence Agency. The Man with Red Eyes says to her:

"My, but the little miss is impatient! Patience, patience, young lady." Meg did not tell the man on the chair that patience was not one of her virtues.

Mrs. Whatsit tells her she needs to lean into her "faults" to help her fight IT and the evil that covers the planet Camazotz. When Meg tries to think what her greatest faults are, she comes up with the following: 

Anger, impatience, stubbornness. Yes, it was to her faults that she turned to save herself now.

Because of her impatience, she is not going to wait or rest to save her father.