Optical illusion is an interesting thing; the way an image can have multiple simultaneous meanings to your buttery-smooth cognitive tissues, but once made aware of them, your salty-sweet jelly orbs can see how each interpretation was present all along. This doesn't work on us higher-ordered entities, mind you, but enough of us understand the principle well enough that it's precisely how we can reach into your unprotected perceptual spheres and sample that juicy neural pudding of yours before it ever catches on.
Imagine, then, a similar principle at work as young Willis began to lose his cool. In the simplest and most physical sense, it was rather like a single, tiny mushroom deciding it has had quite enough of all this and would rather go home, but cannot do so without pulling its mycelium up out of the ground. But as more and more of the fungal network uproots from the churning soil, you begin to realize that it was the soil, and the rocks, and the trees and maybe even the air.
Had you been personally present for his little breakdown, you might have felt foolish for ever thinking the space surrounding Willis was ever anything other than More Willis, and this is the point at which even us higher-ordered entities would rather cheese it than hover around waiting to find out how much we were also always More Willis, which ironically would not affect you quite as easily, with your ingrown cores and your uniquely blunt definitions of the self. Perhaps that's why some would prefer to consider you "differently adapted" rather than "lower-ordered," but that's not a debate this narrator has any investment in; food is food, if you ask me.
Whatever the perceptual levels at work, Isaac knew a problem when he saw one. In his foggy-minded way, he fancied himself a bit of an expert on seeing things and on knowing what they were, and he wasn't terribly far off, even if it still boiled down to a system as basic as "good thing to be seeing" or "bad thing to be seeing." It certainly hadn't failed him yet, and in this case, he knew precisely what to do.