Do you understand this French pun?

I read the comic book "Asterix et Cleopatre", and I don't understand the joke of one passage. Roman soldiers tried to get through a barricade but were repelled. The general tells them to try again.

Soldier 1: "Mais on vient de se replier" (But we just retreated)

Soldier 2: "Déployés, on va se faire égorger" (Deployed, we're going to get ourselves butchered)

Soldier 3 (with a smile): "égorge déployé" (Butcher deployed)?

Then another solider says that if he hears another play on words like that he's going to desert.

I must be translating something wrong. Or, because the book likes to make references to historical events and things going on currently (in this case, 60s), I am not getting the reference.