What happens to paul in tribe?

Answer 1

Paul ran off, supposedly because Lex bullied him. He is never seen again and remained missing until the series ended. *SPOILER* He is mentioned during the book The Tribe - A New world after Bray had met up with KC and Alice in a slave camp prior to being shipped to various locations for laboured servitude, and heard tales of the guardian resurfacing and even that Ryan was still alive and had been transported over seas where he had met up with Paul which would suggest that Paul and Ryan were overseas in a slave camp together alive. *SPOILER*
The tribeheaven website posted interviews with some of the cast members last year as part of a 10 years gone feature. Zachary Best, who played Paul, gave his version of his abrupt exit from Behind the Scenes. See the link below.

Answer 2

he ran away because lex scared him