Punctuation of "what?" in the middle of a sentence?

Question

I'm transcribing an interview and the man says, >"There were, what, 4,000 people at the concert." I'm not sure how to properly punctuate this. He's asking "What?" in the middle of the sentence as a rhetorical question or perhaps talking to someone off camera. It's hard to say if the full sentence is a question or not. (He's British, if that helps!) My ideas: >"There were, what, 4,000 people at the concert?" >"There were -- what? -- 4,000 people at the concert."

Answer 1

Hello! I think your first transcription works best, where "what" is in between commas. Another possibility is the following:

There were...what? Four thousand people at the concert?

Since we often don't speak in full sentences, it's fine if a transcription has a few fragments.