By the lion's mane
"Okay, the silver is the carrot, and the room itself is the box. So, who comes along to eat the rabbit? And are they equipped if the rabbit turns out to have fangs and claws?
"And if we're in the role of the rabbit, what can we do to make sure the box doesn't drop? Or should we just abandon the carrot and go look for something else?"
Mario frowns and returns to the watertight door, checking for any sort of mechanism that could force it shut (trick hinges, sliding levers, etc.).