It has four internal drive bays and room in the lower optical bay.
You should never be without bootable backup of your system, ie "clone" made using Carbon Copy Cloner or SuperDuper or such.
Even if just a FW800 for emergency maintenance too. All that is needed is likely 200GB partition for a system.
I have no idea what support got those ideas but Shift Key is safe boot.
If you have Lion they should have instructed to use Recovery Mode - command-r