Now that you've successfully joined the Berserkers and gained the rank of Warrior - next up is the rank of Paladin. Now, if you've been playing both sides of the Claw vs. Berserker playground - this is the mission where you have to make a final decision. In the On The Road To Becoming a Paladin Mission, you'll have to make a final choice - Claws or Berserkers?
One note: You'll need to be Level 30 for either option.
Help Rat (Choose the Berserkers) / One Last Show of Loyalty Mission
If you want to keep with the Berserkers, head over to The Crater, and use your jetpack to get up on the balcony to the left of the entrance to Hector's building. Head in and to the left, and open up the not-locked safe to get "Hector's Book of Claws" for Rat.
Take it back to Rat, and give it to him. You'll gain a bunch of experience, and get to keep all of the Elexit that Rat gave you before. If you're level 30 - now you can become a Paladin!
Choosing this option ends the ability to work with the Claws and cancels the "The Way of the Outlaw" mission for the Claws.
Choose the Claws (Outlaws) / The Way of the Outlaw
If you want to keep moving forward with Yasma and her band of Claws, you'll need to steal the Guard Rotation Book from the Barracks (1st floor) outside of Rat's tower. It's a simple safe, and the code for the Guard Safe is 9813.
Head back to Yasma and she'll send you to Hector. Give him the book, and he'll let you know that you can join The Outlaws (must be level 30), but that you'll have a harder time climbing the Berserker ranks now. In reality - going back to Rat, either way, he'll let you know promotions are canceled, ending the "On The Road To Becoming a Paladin" mission.