The enemies will have respawned when you return so fight them again if you wish. Run out of this room and all the way along the corridor, through the elevator, to the other side. Collect the Gale Ring just ahead and then pass through to the next room. Two Varcolacis will swoop down as you enter but are easily dealt with.
After the battle, open the Treasure Sphere in the room for 2x Rainbow Anklets then board the elevator and select the Sixth Tier.