Beside Karkat (and yes, he has indeed noticed the troll moving closer, though he gives no outward response beyond taking a casual step closer to Karkat in return), Allen also sags slightly when the Wood Seal's effects fail to hold. It barely lasts for a second before he's shrugging it off with a light, "Oh well, I don't think any of us actually believed it would be that easy. Shall we see about that fire instead? I can dig us a fire pit, just tell me where's the best spot to do it."

He lifts and clenches his left fist to illustrate his point, though the significance may be kind of lost on Karkat. Speaking of, what is Karkat up...

...

Ah, landmarks.

"We can leave a trail of pebbles between each pointer―" Because that's what those things are meant to be, aren't they? "―to help guide people along, too."