SOS from Tandemaus?

Mollie is performing a medical checkup on the Pokémon as the Brave Olivine is docked after a storm, but as Liko is taking her Pokémon there for their checkup, Hatenna senses someone. Believe it or not, it turns out to be a single Tandemaus that has gotten onto the ship. Tandemaus normally operate in pairs, so it's strange for one to be alone like this. Maybe something serious has happened?