The fact that an octopus, with the adorable name Inky, was able to escape its tank (and escape to the ocean by way of a laboratory drain) isn't surprising. No, what's surprising is that Inky didn't cause comical and expensive trouble. Octopi are notorious escape artists. A 10-year-old paper from the Journal of Applied Animal Welfare Science, titled "Interspecific Evaluation of Octopus Escape Behavior," is meant to hinder this very specific problem — it's that common!
I think Inky should be praised for simply leaving the laboratory. Other octopi might have disassembled the entire lab. Because if there's one thing octopi are better at than escaping, it's causing hijinks. They are the Ashton Kutchers of the animal kingdom. Here's an octopus in a trucker hat:

In 1875, Brighton aquarists discovered octopi were sneaking from their tanks, across the laboratory, and into other tanks full of lumpfish. After feasting on the less wily fish, the octopi made their way back from whence they came.
As The Washington Post notes in its story on Inky, an octopus flooded the Santa Monica Pier Aquarium in 2009. The Los Angeles Times described the occurrence saying, "The guest of honor in the aquarium's Kids' Corner octopus tank had swum to the top of the enclosure and disassembled the recycling system's valve, flooding the place with some 200 gallons of seawater."
Eight high fives for Inky
Davey Jones, an octopus-human hybrid, appeared in 2006 Pirate's of the Caribbean sequel, Dead Man's Chest, and debatably torpedoed the sea-sailing series.
In mythology, the octopus inspired both the Gorgon and the Kraken, monsters famous for killing those who cross their path. And in modern culture, the octopus has represented everything from the ills of the industrial revolution to the encroaching surveillance state.
Inky the octopus, contrary to all the previously mentioned troublemakers, simply made a minor party foul by leaving without saying goodbye. The scientific paper mentioned at the top of the story begins, "The study gives husbandry techniques to keep captive octopuses contained. This first interspecific study of octopus escape behavior allows readers to make informed species-specific husbandry choices." I have to imagine scientists who studied Inky the octopus read this paper, and yet, Inky the octopus escapes nonetheless. This proves that no matter how smart or prepared we humans may be, octopi can — and sometimes will — outsmart us.
Godspeed, Inky. May you not be immediately eaten by a dumber, but larger sea creature.