I think what's truly scary is that when Trump is under pressure he tends to try and deflect attention onto something else. In the past, many autocratic leaders "solved" this problem by starting wars, and lately Trump has ramped-up his verbal attacks on North Korea and Iran. However, a deflection by him may take a different course as we're seeing with his condemnation of the media, whereas a recent poll of Republicans has it that now 51% of them agree with Trump that the media is "the enemy of the people".
Or what if he is to be removed by the Senate as the final act of impeachment but refuses to leave, calling out the military as Commander-In-Chief to "protect" him? Or if he refuses the same if he loses the 2020 election?
Or what if he fires all federal officials, including Mueller, has a purge within the FBI and CIA, allowing only his supporters to remain, and then refuses to allow any funding for any investigation against him? Or what if he pardons in advance anyone who's a ""target" or "subject" of Mueller's investigation, including himself?
These are not my ideas but what I have heard or read some constitutional experts say could be possible down the road.