How do you get the last person out from SOS island?

Answer 1

You go down to the very bottom and there is a little switch thing that will turn when you click on it, releasing water that will push the boxes out of the way to reveal a hole into the ballroom. Once inside the ballroom, make your way to the top of the room, and turn the dials on the pipes so that the water bursts the little red sack right above it. Jump up the boxes it releases into the next room. The engineer then tells you to turn the valves to stop the pressure of the steam blocking their escape.