The Activity Club and the House of Frost

You and Isabel leave the room. You notice that the flipping arrows symbol on the door is now glowing red, and the flipping arrows symbol on the door with four symbols is also lit up. Isabel sees the same thing you do and makes the connection.

"I think I'm supposed to be part of the riddle over there," she says, nodding to the door with four symbols. "I'll go check it out. Catch up with me when you can!"

Where do you go now?