“You’re saying that we need to bring in something big or heavy? Like a big rock or maybe an armchair?” Isabela is trying to interpret what Aang’s actions are trying to tell her since the talking couldn’t seem to reach both sides, “Stay there, I will try to bring an armchair over to the mirror.

Well, if they need a big item in order to get Aang out of there, sacrificing an armchair that she rarely uses could be their best option. The young lady brings out one near the mirror over. Now she has never attempted to shove items, let alone furniture, into a mirror dimensions before but she is going to try and make it work.