Not shit, surströmming is fermented herring that smells of sulphur.

A few cans popped open and poured down would probably be strong enough to get through filters.

Also mink piss is a long term stench. There was a mink farm on next to the acre I grew up on and even though it had not been in operation and the buildings were all gone, two decades later when it rained all you could smell was mink piss/gland secretions.

Sealing them in doesn't make them suffer, they signed up for a safe place to ride out the storm they caused. This is just making sure they keep really safe, so safe that they can't make the world unsafe for the rest of us again.