She can't. He can still hear the song, and it's drawing him in, but he's able to fight it somehow. She's obviously telling the truth. Fear flashes back to meet hers in his own wide gaze and then she's turning away from him all over again. His heart squeezes out, unwilling and unable to watch someone else die, even if he doesn't know her. He doesn't even know if she belongs to this place. Does anyone?

Frank dives after her this time, able to kick his boots off once under the water and get some true momentum. His hand reaches desperately forward, waiting to connect with her solid mass, and by the time calloused fingers brush her soft elbow he needs to breathe again. His grab is a rough one, and it won't be easily shrugged off as he breaches the water's surface and takes a deep breath. Blessed oxygen floods his lungs and he blinks lake water out of his eyes desperately to try and assess if the spell can be broken. Like he's some sort of goddamn expert on the matter.