Sounds echoed weirdly in this place--not that Trunks was surprised honestly, given what kind of building it was. Even if it was only in the shape of a building; walking through lonesome places on his own with echoes for footsteps wasn't new really. Currently he's exploring and testing the limits of how much he can sense and making mental maps. The 'books' weren't really 'alive' in the way he expected, so weren't registering any ki as he knew it. It didn't mean it wasn't fascinating anyways...

Then he picked up something; pausing, head turning in the direction of the ki. Another resident? Starting to move in that direction, and then the echo of words had him jogging a bit. That hadn't sounded like a pleasant echo.