Consider the danger he will be in just prior to release. Perhaps Lin's tweets are meant to keep POTUS safe by basically informing the Deep State that he (Lin) has everything Trump has, and if anything happens, multiple other people are primed for release.
This warning is not just a warning from Lin but also a warning that people other than POTUS know EVERYTHING.
Indeed, I worry airforce1 will get shot down or a JFK like event, he should be sealed and safe for the foreseeable if you ask me.