It's a small rune, Evanesco should vanish it into non-existence easily - leaving the group free to disperse fast

(She hasn't displayed her magic front and center in front of the known and declared Templars, out of an abundance of caution, but needs sometimes must.)

Of course, there is the explosion that preceded this to account for. Her balance is out of whack, her ears throbbing with pain, and the aim is frankly shit.

She aims that stick and shouts, louder than necessary, "Evanesco!"

The rune remains, but the plume of smoke sort of blips out of existence. For a few seconds.

(So she's sending Morse code now. Smoke signals.)

Frustrated, she shakes her arm and does it again. And again.