My understanding of it, this was set before tokyo drift... so theres another opening as they left tokyo drift open it runs along side tokyo drift. at the end, when brian and mia break him out of the prison van (ok you dont actually se it ) he leaves for tokyo and he gets there to find that han has been killed. thats why he said at the end that he knew han. answered a key question, because nobody knew ho dominic knew han when he appeared at the end of tokyo drift.