Take it to Aggie and she'll make a yellow skin paste. Every time you go into the slug's cave there will be a need for another OSRS Power Leveling. Return to the lair with five rubium ores and you'll use the paste on yourself. If your space is damp, heat it up with a few rubium ore. Rubiums can be used to make rooms warmer.
The slug-possessed people are likely to be frightened. Transfer to the next room and Mayor Hobbes and Mother Mallum are panicking because they know there is an intruder. They flee the room. To get rid of them, it is necessary to dry heat the area. First it is necessary to remove the water. Do not bother now as the room could be re-soaked.
Visit Falador and contact Savant. Savant will recommend using rubium again to heat the water, then using an increase in Fire Rune to ignite the place. To obtain the purest chunk, teleport to the Rune's essence by using a rock hammer or an hammer.
Make this at the Fire Altar. Take 5 rubiums more from the bank. To release the flames, return to the Slug Lab. Then you're able to move to room number 3. The conversation will begin once you walk in OSRS Gold For Sale. You will start a conversation as soon as you enter.