Translation:And what if he had not brought the gun?
The female voice has an incorrect pronunciation of the word trouxesse. The stressed vowel has the open e, as in the word bed (/bɛd/) of English, but in the audio it has the closed e, as in the word cake (/keɪk/), but just the first part of the diphthong.
The word trouxesse is pronounced "trouxésse" (/tɾow'sɛ.si/).
In speech, it is possible to drop the "what" from this question particularly if it is said with a rising intonation at the end. And that would be a more literal translation which duo would normally accept - not this time though. (I am not sure about it in Australian English however, in which every sentence sounds like a question to this UK English speaker!