I agree that it should never have been done given the high profile nature of the prisoner regardless of whether he was suicidal or not. He should have been given the highest surveillance based on the who he was and what was involved. Forget about suicide watch, which is really a distraction.
The warden can override the psych. It’s also a security issue, as I indicated, independent of the psych analysis. When you have a prisoner like him, you err on the side of caution. This is not a typical situation. Lastly the predictable outcome proves they were wrong.