Board Thread:Show-Related Questions/@comment-92.25.197.157-20141106213112/@comment-25112275-20141106214704

Monroe asks Bellamy how he survived. Bellamy explains that both he and Finn knew the ring of fire was coming and they ran.

I speculate that they were close enough to the secret entrances that they were able to get through one before the rocket's went off. After that I guess they got separated.