chapter 8-in the house of the tisroc

So Aravis is trying to escape the town of tashbaan to meet up with Shasta at the tombs so they can being their journey all the way to Narnia.  However she gets separated and must find a way to get out of her situation.  Her and her friend both sneak into the Tisroc's conference room because it's the only way to escape without being noticed and find themselves trapped when the Tisroc himself come in with his son to talk.  Personally I don't see why they couldn't have just walked out the front door.