Red Dwarf, Series VIII

[Lister has signed up for the Canaries]

Lister:
What have I signed up for?

Rimmer:
In the 19th century, when miners went down a pit: they'd lower a canary down first, in a little cage. [...] And if the atmosphere was noxious, as it frequently was, guess what the canary did?

Lister:
Complained to the Foreman?

Rimmer:
It died, Listy! The canary's job was to go into the most dangerous, unpleasant and most smeggy situations and see if it could stay alive. Then they'd know if it was safe to send in the important people. [...] How come you've never heard of the canaries? They've got recruitment posters all over the men's bogs! How come you've not seen them?

Lister:
When I'm in the men's toilets in prison, Rimmer, I tend not to look around; d'yknow what I'm saying? It's like playing Golf; I concentrate on my grip, keep my eye on the ball and try not to veer off to the side!