Interesting thing to note is that presuming this is Clay Tunnel these are the Pokémon that can be found there in the games:
Pokémon Found in Clay Tunnel:
Basuclin(both Red and Blue Stripe forms.)
So given the fact that it seems like Durant is one of the Pokémon showing up in upcoming episode and the fact Durant is one of the Pokémon that can be found in Clay Tunnel maybe this is the episode that will feature Durant, if that’s the case it could also be a case where Goh catches Durant here.
Blah. The Pokémon World Tournament is in Driftveil City so I was hoping the writers would save Driftveil for a PWC episode but I guess not. Crossing my fingers for another episode to focus on it, if not whatevs ¯\_(ツ)_/¯