What if this is like inception where there are multiple simulations of Zeta Halo each within the other? With the deepest ones being where you trap and lock away the most dangerous of creatures.
We see that the Xalanyn were locked in these devices and trapped by Halo. So presumably it was altered so that it’s pulse would, bit like the composer, lock them away. The rings within rings would thus refer to a Matrix style simulation of the ring that these trapped creatures live through.
Also, little suspicious how we got knocked out for six months and woke up in Westview. I am just saying, it’s all a little convenient as we help not Cortana stop the Xalanyn escape whilst being sent visions on a pre determined path.