Does Firefight mode have rankings?

Also how the heck does it work exactly. I jumped into a match last night and I know they enable the skulls to make things more difficult as the waves progress. How do you open doors to get more health on some of the levels?Does Firefight mode have rankings?
I dnt think there is ranking, the health is always where you originally spawn but i think there only 4 packs per section of wave. from what I understand there are 5 waves and 3 parts to each wave, and then 5 parts to each of the 3 parts. It can last forever and is really fun.random skulls turn off and on throughout every wave.Does Firefight mode have rankings?
Ok thanks, On the first level that the game defaults to when you go to Firefight mode I noticed that the room you start in or right in front of has the health packs and the doors have a green light on them. When you walk close they slide open. As my game progressed i used all the health packs up and went lurking around the level. I found a few doors with red lights on them and then another door with a green light and was like sweet more health packs but sadly the door would not open. I was wondering if there was a way to get it open or if it was a level thing that would open later when things get harder.
Off topic but one thing I noticed is that the graphics look sic. Much better than halo 3.
yea the graphics are way better then halo 3