  We explore the escape geometry of four electrons a few eV above threshold
following single-photon absorption from the ground state of Be. We find that
the four electrons leave the atom on the vertices of a pyramid instead of a
previously-predicted tetrahedron. To illustrate the physical mechanisms of
quadruple ionization we use a momentum transferring attosecond collision scheme
which we show to be in accord with the pyramid break-up pattern.
