[welshwelsh]

You might be overestimating the effects of hallucination. Someone who's hallucinating is not necessarily more impaired than someone who is drunk.

Imagine this- you hear something behind you (a real sound), and for a moment you are startled, thinking someone else is in the room. You soon realize that this isn't the case.

Someone on hallucinogens might take a moment longer to realize that there is nobody there. They imagine the intruder a little more vividly, their heart rate goes up a bit more. But just for a moment.

In contrast, if there actually is someone there, a drunk person might not realize it. Their senses are dulled. Instead of seeing things that aren't there, they fail to notice things that are there. It's the opposite.