Silent witness

Re-watching some Ridley Scott movies on DVD recently, I noticed a recurring motif: pivotal death scenes featuring a passive, non-human observer:

Alien: Jones the cat looks on as the xenomorph claims its first post-natal victim in Harry Dean Stanton.
Bladerunner: A genetically engineered owl—of course it’s not real—pays scant attention to the brutal killing of Dr. Eldon Tyrell at the hands of another of his creations, Roy Batty.
Gladiator: During the combined patricide and regicide of Marcus Aurelius by his son Commodus, the camera comes to rest on a bust of the emperor within sight of the murder.