I noticed a while back that the Mortiurge alternate rank 5 for the Arbitrators lacks the talent Nerves of Steel, which is the prerequisite for their talent Last Killer Standing. Now, this could be an oversight, as Nerves of Steel is a part of the normal rank 5 scheme, or it could be a factor to balance the access of the talent. After all, by the RAW, it's still available as an elite advance at 50% above what the normal rank pays.
Thoughts?
-=Brother Praetus=-
Keep in mind you're not obliged to take the alternate rank at the minimum possible entrypoint.
In fact, if I recall the arbitrator career scheme well enough (my friend built a Rank 6 arbitrator/immoralis warden(1)/mortiurge(6) from scratch for one game), it might be more adantageous to hold off until rank 6, where one doesn't "lose" as many useful skills and talents.
I'm aware that the rank requirement is merely the minimum and in no way is one required to take it right at rank 5. Additionally, any skill or talent whose prerequisite was part of the original rank is still available as an elite advance at an additional 50xp; per the Elite Advances from Missed Careers side bar on pg. 53 of the IHB.
Actually, the more I look over the Mortiurge, the more I wonder if it was intended for rank 6 and not 5. Much like the Moritat.
-=Brother Praetus=-
Call me a "Naysayer", but if there is one possibility and the other possibilty is that the rules are "broken", I tend to think the later to be the cause.
Never the less, due to the "buy it +50" option I would simply say "use it that way". In my case, this is a "bug" that comes equipped with a fix for it. Which is fine 
Correct me if I'm wrong, but I read the IH as applying the "+50" premium cost only as an option of picking skills (and perhaps talents) that are prerequisites of skills/talents you wish to purchase, not applying to just anything you missed out on, RAW-wise.
Not that I'd go down that route, but I think it helps to know exactly what the rules are stating before one sets out to use them in whatever way they wish.
The Hobo Hunter said:
Correct me if I'm wrong, but I read the IH as applying the "+50" premium cost only as an option of picking skills (and perhaps talents) that are prerequisites of skills/talents you wish to purchase, not applying to just anything you missed out on, RAW-wise.
Brother Praetus said:
Additionally, any skill or talent whose prerequisite was part of the original rank is still available as an elite advance at an additional 50xp; per the Elite Advances from Missed Careers side bar on pg. 53 of the IHB.
Correct, which is what I stated in my post; copied, quoted and emphasis added here for convenient reference. 
Easy enough to miss both here and in the book, so many of us seem to skim content more often nowadays. Of course, I've been working on trying to get all the medicae related stuff from the Chirurgeon rank of Adept since I missed it when I went Calixian Xeno-Archivist, and we desperately are in need of a skilled medic beyond our tech-priest.
-=Brother Praetus=-
Herp derp derp herp, my bad for not fully reading the posts and checking when Arbitrators actually do get Nerves of Steel.