If the government wanted him dead so bad in the past...
It was mentioned during one point in the movie, that the government tried everything to get rid of Jason. Hang him, firing squad, the chair etc; but they never succeeded.
My question is: If they wanted him dead so bad, why didn't they just cut his head off and throw him in the middle of the ocean. There was no possible way how he could regenerate a new head in the ocean, and even if he was able to regenerate a new head, there would be no possible way how he could get back to land.