What if the drugs were dissolved and then injected in his food or added to his drink? Wonder if they would be detectable or tasted by Daniel.
And I still think he was given chloral hydrate in something he drank.
When I worked in a hospital many years ago, there was a little door in each hallway. It was a chute to an incinerator.
I remember it because one of the nuns took a "dirty book" from an old man (before viagara) and threw it down the chute.