The idea that airports (or the transit areas of airports) are somehow extraterritorial and not part of the sovereign territory of the nation where they are located is a popularly-held belief which is entirely untrue. You'll notice that police of the host nation operate in these areas for example. For example, see https://english.elpais.com/elpais/2013/06/27/inenglish/13723... but there are hundreds of sources for this if you search online.