Factual error: John Smith's (voiced by Aussie, Mel Gibson) accent changes and also fades in and out during the course of the movie.
Factual error: The flag used when Radcliff claims the land for King James I wasn't adopted until 1801.
Factual error: The movie depicts a moose in what would be Coastal Virginia. They are not native to there at all.
Answer: He probably knows that if he tries to escape he'll be shot down by the Powahatans' arrows. He prefers dying with some kind of dignity rather than while running.