The article doesn’t say how many Democrats voted in favor of the inquiry, but if the vote was 15-14 against then at least 3 or 4 must have voted with the Republicans (Democrats have far more than a one-vote majority in House committees).
Thats what I was thinking also. The Repubs on the committee wouldn’t have brought up the issue if they didn’t think they had a chance of getting it passed. Maybe Rahm made some calls