You are so right. Because Trump is a loose cannon. He knows nothing about being a President. Doesn't have a clue about Separate powers or the Constitution. He is going to just do what he wants. Not that he couldn't be President and be effective at it. His problem is that he is a one man operation. He doesn't want to listen to anybody and that is why he leaves a trail of destruction to the people he hired. They know what they are doing but he doesn't.
It wasn't just the press conference either. Its tied to the Gordon Sondland testimony:
Excerpt from article at this link
https://www.politico.com/news/2019/10/17/gordon-sondland-to-break-from-trump-in-impeachment-testimony-000288While Sondland was testifying behind closed doors, acting White House chief of staff Mick Mulvaney acknowledged for the first time that Trump decided to freeze critical military aid to Ukraine unless the country investigated the “server†theory. It was a stunning public admission — one that Trump and his allies have denied for weeks, and one that Democrats have been trying to substantiate through a series of closed-door interviews. Mulvaney, however, later walked back the remark.
“I think Mr. Mulvaney’s acknowledgment means that things have gone from very, very bad to much, much worse,†House Intelligence Committee Chairman Adam Schiff (D-Calif.) said.
Rep. Eric Swalwell (D-Calif.), a member of the Intelligence and Judiciary committees, said Mulvaney “co-signed the president’s confession,†adding, “The president has pleaded guilty to the crime. It’s just a matter of, what should the sentence be.â€