She couldn't see his movements per say, but after dating a speedster for a number of weeks, you learn to recognise a few signs. That blurish image from the corner of your eye, for example.

"I didn't know vampires were super fast," she stated conversationally, grinning as she began preperations for leaving the planetside. "I'm so going to have to get you to take me for a ride now."

Without waiting for any sort of questioning response, Jenny continued. "I'm a soldier. All children of the machine are born with the skills and knowledge necessary to make them the perfect battlefield trooper. Kill or die trying -- it was all I was ever supposed to know, Edward."

She glanced at him briefly, looking more serious and thoughtful than he ever probably saw her.