Orbitals and electrons....
An orbital is not a thing, nor does it have an "inside" or an edge. Even if you could see an atom, you couldn't see an orbital. An orbital is a mathematical construct. An orbital only has a shape because we ascribe one to it based on the range of probabilities of finding an electron in an atom.
Based on the results obtained from the Schrodinger wave equation we can ascribe a spherical shape to the s-orbital. The sphere has no definite edge, it just fades to almost zero as the probability of finding an electron at increasing distances diminishes.
By the same token, the probability of finding an electron increases moving toward the nucleus. So how would it be possible for an electron to pass through the nucleus? An electron is not a thing, either. It's not so much a particle as it is a wave.
And as Feynman said, "if you think you understand quantum mechanics, you don't understand quantum mechanics." There's always something to become clearer and some "ah-ha" moment that you hadn't had before.