Oh no, it seems that the crocodile has a toothache and the other dentist just left for the day! Time to roll up your sleeves and get in there, but careful of your fingers!
You don't need to catch them all, just certain ones, but those ones you REALLY need to catch. Or someone else will catch the ones they need and then the game will be over. Plus, think of those poor pokemon, stuck in a maze, all alone. Just dreadful.