changed glass each side of exit door, for light bridges, connected to a pedestal button, above exit door.
& changed glass, in front of exit door, to grating.
changes to stop traping the player.
spotted by sentientcloudwastaken.
thankyou sentientcloudwastaken :)

update thanks to jade BGE for finding an unintended solution, bypassing the use of the 2nd sphere.
made portable floor in entrance area, non portable.
also added glass, to exit door, to stop franken stacking, to reach exit door.
it would have been difficult, but possible, just about.