Halo 3 terminals......how the hell? and 1 skull

[want2bAbronco2]

spoilers.....so if you don't want to know where the terminals are, 1 of the skulls, or some of the plot, don't read.










How the hell do you get that achievment? I know where all 7 of the terminals are (unless there are more, 7 right?) and I have gone up to each one in co-op and RB them....read the stuff.....and it doesn't unlock the ach. I am starting at the begining of each lvl and not starting from rally points. Is there something that I am doing wrong?How come?

Also.... how the hell do you get the cortana skull? I have played it single player/co-op and jumped through the damn rings every which way, spent 3-4 hrs and still can't unlock it. Anyone have the ring order to jump through, maybe mine is incorrect. Also which side do you start from after you kill truth? Thanks for any help!