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To undertand that it's a very uncommon event, we can ook at Yuri reaction.
Yuri was aware of Baam entrance when he got in, it means that Headon isn't the only one to "be informed" of an irregular arrival.
I'm not sure, but I think that Yuri states herself that it's the first irregular since Mazino.
So if Headon was failing another irregulars, the rest(at least some high ups) of the tower would be aware of that;