Code Green is when you are in need of marijuana. An emergency, if you will.
Me and George ran out of weed. This is a code green.
When you have run out of marijuana, and need some more.
Raditude: Yo, we're code green here, can you hook us up with an O Z, for 90?
Dealer: Sure, come on by.
Raditude: Hey man, load another bowl.
Friend: Dude, we're code green.
Raditude: Dammit, this sucks.