The sudden surge of strength genuinely takes Liu Mingyan by surprise; she is used to a vast array of demonic and cultivator trickery, but she knows of no talisman that can change an opponent's abilities in the thick of battle. She could try to resist, and may even succeed, but it would sorely tax her, and she's not sure she could free her blade rather than just refusing to relinquish it.

So she doesn't. She lets go of Cheng Luan's hilt and ducks under Janet's arms, grappling her around the waist and bearing her backward onto the grass.