You are with 4 SMG4 crew members, inside of what used to be Peach’s castle, which is a hell cave

SMG3: “This isn’t Peach’s castle, this is a hell cave!”

Meggy goes into part of the cave, but gets captured and took away

4, 3, and Mario: stares in disbelief “AAAAAAAAAAAAAA”

SMG3: “GET THE SPRING PAD, WE’RE GOIN’ OUT OF HERE!”

Mario: “I THOUGHT YOU HAD THE SPRING PAD!!”

It’s just you, 4, 3, and Mario. Peach is now a terrifying creature, and everyone else is on the surface.