It's been a while since she's kissed anyone, but... this is not what's supposed to happen. Even if it takes her a moment to realize that Walter is just... not doing anything. He's not even breathing. Is--

Is she doing something to him without realizing it? She breaks the kiss and pulls back. No, he doesn't look any different. He just... oh. Oh. Right. "I-I'll just-- I--" If she were still alive, she'd be having a hard time breathing right now. As it is, she still can't finish a sentence. She backs away, down towards the water.

"I... sorry." She turns to disappear into the lake, stumbling a little in her haste to just get away.