As being invited, teams should first build a steamship. Independent of which two ship's funnels are chosen, "INNER SQUARE LETTERS CLOCKWISE" appears around the ship. So now let's follow this hint, disassemble the boat, fix a stick in the central point and rotate it clockwise, staring from 12 o'clock. Reading
out letters in the dashed square gives D25 FIRE ESCAPE STAIRS TOP LEVEL.

CREDITS: This page for the steamship building instructions.