Why would Jim still be in the UK?

Boyle and Garland have already said that Jim will be in the sequel to 28YL, but why? It's been a while since I watched 28WL but I assume that the US military Would have rescued the survivors of the first Outbreak and given them a choice between staying in England or leaving for another country And personally if I were Jim I would never want to step on that country ever again What are y'all thougths about this?