AThe witch found her eyebrow quirking a moment, Una's ideas causing the snakes within her to squirm in anticipation. Anyone in the group might have seen the black flicker of a little serpant flash from her lips and disappear again in the blink of an eye, much like a spark of electricity. Whether they saw or just thought it a trick of the light, Medusa didn't really care. If her comrades stuck around after the first phase, they would see a lot more than a quick glimpse of her powers against Lina.
"I wouldn't want to hinder on your amusement. Besides, I can understand that most of us would prefer giving ourselves away in the plain sight of an Asgardian. I trust your discretion. If Lina Inverse does see you...let it be when it's too late for her to retailiate." she replied simply, put emphasising the point of not giving their target a chance to fight back. Not like she had played fair creating a crater next Niflheim.
Confident she got her point across, Medusa waited for anyone else to interject, or give the all clear that they wanted to set the plot in motion.