Swamped

Looking more closely, you see some shapes cut into the surface of the corner chamber. They look like someone's touched them a fair amount.

You don't think these symbols are actual controls - rather, there's a device elsewhere that reacts when they're touched. You could experiment with what they do, but that could draw attention and you're not sure you could trace the signal, since it's most likely ethereal.

What you can do is look for other signs of the operator's trail. And really, they're fairly obvious now that you're focused on them. However, there's no guarantee they'll lead to the control device soon; but it's something.

Of course, a trail goes two ways. Should you focus on where it came from, or where it's going?