Full mechanical disclosure (so that you understand what's happening game-wise) Sir Darfin was beat down to zero HP non-lethally and imprisoned in Iron Bands of Binding (in case he woke up). Everyone is vaguely aware (Tommi perhaps most aware) that this room belongs to the Floshin family (it had been a family secret up until now, but it has been here for hundreds of years, at least since the time of Darfin and Shalendra's father Elorfindar. It can have up to three portals open at once, on each "side" (the room is round, but you get my drift). Shelendra was not concentrating on the portals, but she WAS making the whole room bigger, in order to move large numbers of troops through (it's normally just door-sized portals. One person at a time. The Floshins generally use it by themselves, and sparingly).
Tommi saw the ruined castle through the north gate earlier (though he didn't know where it was or the name of the place) but the west gate is closed now, and the east gate is going to a different place now (he saw what looked like an elvish hall earlier, but now it's some kind of Thayan Orc Army Barracks.)
Yes, I should point out (if I haven't made it clear yet). These orcs are not the same as the local orc tribes outside. They are armed an armoured in an unusual, foreign style (it seems pretty likely that they are from Thay - stories of Thayan Orc Hordes (enslaved and trained to serve usually from birth by the Thayans) are told by bards. Generally less "feral" or "barbaric" than most Sword-Coast orc tribes. Then again, those have been pretty organized lately too. (It's almost as if they are generally underestimated by "civilized" folk).
Anyway, it does seem likely that Darfin might be able to close the portals. Anyone trained in Arcana might be able to figure it out. Gimme a roll if you're trained in Arcana. Untrained just doesn't seem likely to me, regardless of Int roll. I dunno, maybe gimme an investigation roll if you're not trained in Arcana. Actually, these checks should require your actions. It would take going over to the portals and having a look at them. Of course, that isn't really possible at the moment with the darkness. Escella can do it, though!