Psi Cop - am I missing something?


I was looking through B5 2nd edition and I note that in order to become a Psi Cop (prestige class) one has to have a P rating of 12.

I have been looking but it seems that the most a PC could have is 1-7 as a p rating (due to the 2d4-1 roll to determine p-rating).

Did I miss something?
Are Psi Cops limited to NPCs? and if so it should state somewhere.

Thanks and sorry if this is a dumb question.
Starting telepaths may forgo their 1st level Telepathy feat to gain a +6 bonus to P-Rating (page 52). And the P-rating range of a 'regular' telepath is is 2d4-2, not 2d4-1, giving a range of 0 to 6, or 7 to 12 if the +6 bonus is taken (pp 103-4).