This article has an image showing the 2S and 2P states of a hydrogen atom. The caption makes the following claim:
The 2S and 2P states of hydrogen show where the electron could be found at any given time. These images show the possible locations of the electron in each state; the proton, unmarked, is at the center of each image. In the 2S state, the electron overlaps the proton, and for a non-zero amount of time, the electron is inside of the proton itself. In the 2P state, the electron and the proton never overlap.
My question is about the statement
for a non-zero amount of time, the electron is inside of the proton itself
It doesn't make sense to me that the electron could be inside the proton. Does that actually happen, or is this a simplification?