Ilon more or less uses this to say, “Fine!” which can be read in as many ways.
([soft] hh-[glottal stop] GHEE)
With the glottal stop in there, this is air filler like, “Well, well …”
When Ilon utters the musical “O-oh-OH”, he is giving a flat “No” in Ondoko. Tonally it may sound to an English speaker like a kind of question.