She allowed herself one drop of liquid luck before her array's first trial. It gave her the inexplicable urge to back up, seconds after activating the circle.
So she did.
Right into a bag of floo powder.
BOOM!
"Ah, it seems chalk is not the right conduit, after all." Dumbeldore nodded, to himself.
She shrugged, shaking the floo powder off her robes. The green dust floated over the array, causing it to glow.
"...l guess I'll try again? With floo powder?"
"Quite."
This time, it worked.
"What now?"
Shocked eyes locked with twinkling blue, "uh...hide the muggleborns?"