Ask if you can help them.
From Create Your Own Story
You ask about assisting them with their siege.
"Ah, yes, Uren and I have been attempting to hold off these goblins for two weeks. Two long weeks of blasting those goblins open. We don't really attempt to push forward at all. Our goal is mainly just to stay alive."
"What could I do to help?" you ask.
"Well... first things first, we need food. To my understanding, the nearby minor Cempostash has a supply of food. Could you check there for it? They may have more then just food..."
You, of course, agree to do so, because you know your only way out of this hell-on-earth is through your allies. You step towards the corridor, when suddenly you feel some pressure on your foot...