I wonder if Cliff tripping on acid in the last act is a meta-reference.

When the Manson murders were still in recent memory, a lot of people thought the killers had been on acid during the incident. Read: "LSD is evil; it makes people do murder!" Others thought the victims had all been tripping when they were ambushed. "LSD is dangerous; it makes people helpless and unable to defend themselves, even when their lives are at stake!" And of course, there's the Fatal Vision case, wherein a Green Beret claimed his wife and family had been murdered by "hippies", one of which was chanting "Acid is groovy." Of course, in that instance, it's debatable whether there were intruders at all, tripping or otherwise.

Whereas in this, Cliff is just starting his trip when he's challenged, but no matter: acid doesn't stop his stuntman instincts from taking over. Could be coincidence, but I'd love it if it was a meta-reference!