I wandered around the Saffron City Gym while battling against the Gym trainers inside. I had to teleport around the Gym and I actually got lost a couple of times since to this day I haven't memorized the correct path to take to find Sabrina, but I eventually found her and I battled her. I used my Piloswine against her Espeon and I beat it with Blizzard. I then switched to Hypno and I had it use Shadow Ball to defeat Sabrina's Mr. Mime. All that remained was Sabrina's Alakazam which I defeated with Pidgeot and Ampharos. I obtained the Marsh Badge and I left the Saffron City Gym. I healed my Pokemon and then I went east to Route 8. I battled trainers along the route and I saved before arriving in Lavender Town.