Dhamma - one law, two paths?

I was having a debate with a follower of another faith, and during it, this quandary came to me: Did the Buddha describe one law for sentient beings - that is, the law of intentional action? (I understand he taught 'only suffering, and the end of suffering'...) And can it be said the Buddha described two paths for this law? There is the path for the layperson, who embraces intentional action (as the teachings on kamma to laypeople within the Pali canon point to), and aims for a perfection of intentional action - suffering, but 'limited'. And there is the path of the monastic, who aims to abandons intentional action, for nibbana - 'the end of suffering'. But do they not still embrace the law, by only treading on that part of action that is beneficial to them/others, towards their goal, until that can be put aside? In other words, is the bodhisattva goal rooted in the same principle as the arahant goal? (perhaps clearer - is the path towards nibbana *in any way* outside of the described law of intentional action?)