I remember this scene so vividly in part because I love octopuses, but also because of a comment the professor made: "This is remarkable, because it's really quite rare to see an act of predation in the wild."
Surprising perhaps, but true. Predation events tend to happen very quickly. Predators are vulnerable while they're eating, so they snarf down their food at lightening speeds and/or hide while they're eating--like the octopus.
I was reminded of this story because of a fantastic photo in the news: not an act of predation per se, but direct evidence of a very recent act. This is the sperm whale equivalent of getting a splash of soup on your chin:
From New Zealand's Marlborough Express.
It's a squid arm! The rest of the squid, I'm sure, is being actively digested within. Apparently a whale-watching tour off Kaikoura (on the South Island) spotted this messy diner and snapped a picture.
It must be tough to be a whale, with no opposable thumbs to wield a napkin.