I see where my post above was unclear. For the theorem to apply to a 1+2n dimensional object, the vector field on the 2n dimensional surface of the object must be restricted to the surface - it must be tangent to the object everywhere.

The proton is fully 3-dimensional AFAICT so the vector field on the surface (if it has a surface, I'm not a physicist) can have non-tangent components, pointing inwards or outwards.