×There's quite a lot of briar in the main area. Letting the root reach some of that by destroying the broken walls by the force arrow will slow things down a lot. Of course, you want to clear some out so that it doesn't kill you or destroy the orb. Focus on clearing out the briar near the orb first, then let the root in.

You can also buy a little additional time by re-opening the door to the token before an expansion, then closing it once the three briar squares that grew over it change color.

There's a bit of trial and error beyond that, but that's the basics of it. Once you destroy the root, you can have the fegundo clear you a path out of the room if needed.