The military clearly moved (or strategically chose to indicate they wouldn't move) for a paranoid, military-aligned dictator to be captured by a small force with only naval backup exactly when everybody most expected the US to move. Unless there's a faction there that actually likes Machado she may even be lower on the next-leader list than "Maduro pays his captors off with the contents of his offshore accounts, meaningful promises of oil money and empty statements about cracking down on narcotics trade". I assume he has ways of finding out who his loyalists are and who they aren't too...