This word ではいけないのでしょうか？

Monty: Well, my friend Snowbell here needs a favor.

Smokey: Snowbell? [chuckles] Now there's a manly name.

Snowbell: Yeah, you see, sir, I've got this mouse at home I can't eat.

Smokey: Sensitive stomach?

Snowbell: No. I can't eat him because he's, uh, a member of the family.

Smokey: A mouse with a pet cat?

Monty: Hahah! Isn't that funny?

Smokey: That's not funny! That's sick! A cat can't have a rodent as a master. I mean, what's this world comin' to? It's against the laws of nature!『 Word of this gets out, it'll be bad for cats all over.』

Snowbell: So you think you can help me?

Smokey: Consider it done.
・・・・・・・・・・・・
映画 Stuart Little のスクリプトです。
『 』の中の文 Word of this gets out, it'll be bad for cats all over.
なぜ Word of this になっているかが分かりません。 This word ではいけないのでしょうか？