River watches him go for a moment, her face still and listening.

Then she turns back to the holographic wall, tracing a finger slowly along one light display. When the touch yields only wallpaper, she drifts across the hallway to the other wall, where a series of photos of the Earth from space is more traditionally framed.

River can occupy herself for quite a while, looking at things like this. (Looking at anything, really. But with some things, she can be pretty sure other people will find them plausibly distracting.)