Taako quietly does notice Foster sticking closer to him, and makes a note to tease him about that later, when they aren't busy with way more important stuff.

For now, he does indeed start knocking on things-- walls, the floor, etc., but he makes his way over to what seems like the most important surface to knock on: the dome surrounding the Rose.

He knocks at it gently, and then presses his palm flat against it, curious to see if anything happens.