No. I am not. In terminal three, after checking in to leave Indonesia, one heads to the international departures entrance to the left. There is passport control, security, and then escalators down to all the Terminal Three international gates. If you walk to the right the gate numbers will keep going up, and you will eventually run into a wall/end of the line. On the other side of that wall is Terminal 3 Domestic and a ton more gates.
Back upstairs and "landside" are also all the check-in desks for Garuda, Citilink, and a few other domestic carriers. Domestic passengers walk all the way to the right to the domestic departures entrance. You go through security and down escalators to the gates. At the bottom of the escalators is the same wall mentioned above. International passengers do not share spaces or facilities with domestic passengers like they do in the US and some other places.
While waiting for a flight to Sorong, the international lounges are not an option and they are on the international side of Terminal Three.
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