What holds an IIe power supply in?

["Jayson Smith" <nospamratguyspambegone@nospamplease.bellsouth.ihatespam.net>]

Ok, I'm blind, so this might seem like a stupid question, but...
A while back I, for some reason, took a notion to unscrew the screws holding
the bottom of my IIe on.  Guess I just wanted to see what was inside from
the bottom view or something.  Anyway, in the process, I unsecured the power
supply, and it can now slide freely from front to back.  I know that on the
IIgs the PS hooks into a little place made for it and snaps into place.  But
what in the world holds it in on the IIe?  Because of frustrations with the
supply sliding out of hand reach to turn the system on with the cover on,
I'm temporarilly running it with the supply outside the case and the cable
running through the hole where the switch and power socket normally stick
out.  Is there any danger in this, either to humans, other creatures, the
computer or the supply?  Thanks for any help.
Jayson.