Oh come on, didn't you read the description? The fire giant is both giant and fiery, and has terrible manners. Plus where were you going to go, the lift is a pretty major pathway.
As the party is running around trying to escape, the giant leisurely roasts them or pounds them into squishy marks on the floor. Gothmog fares a little better for a while, since both his soaked cloak protects him from flames, and his fiery eyes make the giant think he's already attacked the mage.
Poor Gothmog is forced to pretend to be a girl, and marries the Fire Giant the next day in a beautiful ceremony
While the story ends well for Gothmog, you might want to save the rest of the party by restarting at 1