Channel power states that "The owner of the psicrystal can manifest powers through the psicrystal to a distance of up to 1 mile. The psicrystal is treated as the power’s originator, and all ranges are calculated from its location."
Since the power originates from the Psicrystal, if True body Switch is manifested, the Psycrystal and target would switch places upon failing a Will save. If you pay the extra power points the change will become permanent and the creature now trapped within the psicrystal can be broken and killed easily.
Your psicrystal is now that creature, yes?