I entered Rock Tunnel since I needed to pass through it in order to get to Lavender Town, and I wandered around the dark for a while. I encountered tons of wild Pokemon, and I battled against them in order to level up my Pokemon. I then battled against some trainers inside the cave, and I found some stairs that led to the next floor of Rock Tunnel. I arrived at the next floor, and I battled some more trainers there. I picked up some items as I was wandering around, and then I finally found the exit. I headed out, and I battled some more trainers outside. I headed south after that, and then I arrived in Lavender Town. I quickly headed over to the local Pokemon Center, and I healed my Pokemon there. I then headed over to the Poke Mart, and I stocked up on important items. I saved before moving on to the Pokemon Tower.