Game On.

Broken tune

The rats surged the platform, thousands upon thousands in a heaving black mass.
Harry was panicking, eyes wide in fear of the rodents. "What do we do? What do we do?"
Cat grabbed his face, turning him to look into her eyes. "Calm down. Panicking never helped anyone."
"Hate to interrupt this touchy-feely moment, but hungry rat swarm coming closer!" Shrieked Lindsay. Cat looked around. There was nowhere to go, no obvious escape root, no weapons or tools of any kind...
Suddenly, she remembered the flute clutched in her hand. Earlier the rats had seemed to be influenced by the music, attacking, retreating and, heck, dancing when it played.
Praying she was right, she brought the instrument to her lips and blew. A long, sharp, piercing note ripped painfully through the air, causing the rats to squeal in agony and shy away. However, the effect didn't last long. As soon as the note finished, they advanced again, eyes burning with anger.
"Well that worked!" Yelled Lindsay sarcastically, kicking at the closest rats. Harry had found some loose pieces of rock and was throwing them into the fray.
Cat felt something tugging her skirt and shrieked, looking down to see a rat climbing up her skirt. She tore off the fabric, shortening her skirt out of the reach of the rats.
Swiftly, she blew into the flute again, delaying the rats momentarily, until she ran out of breath.
The rodents were swarming closer and closer, forcing them to back up, until they were practically back to back.
"There's got to be a better way to do that!" Hissed Lindsay. Cat glared at her "I'm trying! Do you want a go? You can if you want!"

Cat was frantic. They were fighting of rats left and right, and the flute was only a temporary solution. She couldn't even play the flute properly!
But it had to hold the answer. It was the answer to the riddle, so it was the key to the whole thing.

The key to the whole thing.

Maybe the flute was more connected to this than she thought. Maybe the control ran so deep for another reason. Maybe...

She made a split second decision and, praying she was right, lifted the instrument into the air...

And smashed it against a nearby stalagmite.

The flute shattered into splinters with a loud CRACK!
The rats squealed loudly in unison and dissolved into mist.
Cat leant against the stalagmite breathing hard. "Well, I just have a new fear." She gasped.

Lindsay supported Harry who was white as a sheet. "Maybe we should leave now." She gestured with her head towards a lone door. Cat nodded and they all stumbled towards it, supporting each other as they fell through it, back into the library.