After battling your friends on Rivière Walk, you enter the Connecting Cave on your way to Ambrette Town.
In the cave, you may encounter Zubat, Meditite, Whismur, and Axew. You may also have horde encounters with Zubat, Whismur, and Axew.
If you go into the Cyllage City Shortcut (the northern cave), you will encounter Pokémon Breeder Mercy. She has a level 12 Ducklett, a level 12 Pikachu, a level 12 Litleo, and a level 12 Oddish.
Beyond her, there is a dead end, so go back to Route 7 and use the south cave entrance to continue on to Ambrette Town.
Just inside the cave entrance, you find a researcher who will heal your pokémon if they need it. Go west from her to reach Route 8, Muraille Coast.