The last trainer here is a nurse, who will happily heal up your whole team- once you’ve beaten her in a battle.

Battle: Nurse Dixie (1400 Poke)
Opponent: Leavanny Lv 35

Continue up to the third floor of trainer battles.  Going from front to back again, you’ll want to first look left to face an elderly woman.

Battle: Socialite Grace (7000 Poke)
Opponent: Roselia Lv 35

Duck past her to the next row and look left for a PP Up item, then head to the right.  First you’ll face the gentleman who has been watching you approach.

Battle: Gentleman Daniel (7000 Poke)
Opponent: Umbreon Lv 35

Continue right and deal with the last trainer on this floor.

Battle: Psychic Sarah (1120 Poke)
Opponent: Yamask Lv 35, Gothorita Lv 35

Past her you’ll find TM65, which holds the move Shadow Claw.  Thanks to the various interactions of pokemon elements, Shadow Claw is treated as an inferior version of Night Slash- the difference being that while Night Slash is resisted by Fighting-types and supereffective against Ghost-types, Shadow Claw is unable to touch Normal-types and resisted by Ghost-types.  Since nothing is immune to Night Slash and Fighting-types tend to have high defenses anyways, Night Slash gets used more frequently by a long shot.  This isn’t to say that Shadow Claw is bad, and some things that can’t learn Night Slash can learn it, so it does have a few nice purposes.