These monsters look a lot bigger now that you're smaller, and consequently take longer to defeat. You'll face a Stalfos and a Green Bubble. Destroy all the enemies here to open the doors. Crawl through the hole to wind up in a room with two barred doors, a small crawl hole, a bunch of Keese, and an Armos in the center. There are a few fiery enemies to be found here, so equip your Hylian Shield.