Thank you for your thoughts.
I feel that μεθιέναι just like ἀφιέναι, ἐκβάλλειν and παριέναι mean "let fall" in a figurative meaning like "abandon".
I can't see clearly yet if there are examples where it's literally about falling on the ground.
What form is μεθήσετ exactly? I can't figure it out myself and can't rule out that the sentence you've found conveys a figurative meaning too.
I think that I'll may have to do something with ἐάω and maybe ὀλισθαίνω ?