Ah, nicely explained Saiyan. Added some things that I forgot to even. +1 o.o And the lag thing, If you go on the corner to the left of the turret by the computers. And keep shooting, the lag will be there, but you WONT lag out. So just deal with it if you want a perfect run. 
Keep in mind that, that is
ONLY WITH HOST!!!! The rest of the glitch will work in Co-op campaign, but not the corner thing.