It's more spooky and interesting. When we switch to discussing the single particle case, the "wall" is a metaphor. You have a single particle in a low energy st

It's more spooky and interesting. When we switch to discussing the single particle case, the "wall" is a metaphor. You have a single particle in a low energy state at position A. There is another low energy state at position C, but the path from A to C entails (ostensibly) passing through an intermediate high energy state at position B. Without lending energy into the system, you wouldn't expect the particle to be able to move from A to C, because the particle needs a lot of energy temporarily to move from A to B (which it would give up again as it moves from B to C). Yet the particle does move from A to C, in the absence of an energy source that could explain what happened. This raises the spooky question: Did it actually pass through B on its way? It seems like it did not.