The water in the bamboo pipe is welcomingly refreshing.  It also contains a magical solution which will enable you to be exposed to melting-point temperatures without harm.  Discarding the bamboo, you start off north again in good spirits.<br/><br/>The temperature continues to rise and you find yourself dripping with sweat.  As you struggle on, the heat intensifies until it feels like white heat and becomes so unbearable that you begin to pass out.<br/><br/>Although the temperature in the tunnel is higher than you could normally tolerate, the liquid from the bamboo pipe keeps you alive.<br/><br/>Mercifully, the temperature now starts to drop rapidly, and soon it feels almost cool again.  On the left-hand side of the tunnel is a closed door.  It has a small iron plate in it, which might possibly slide open.<br/><br/><em>Your options are to try to open the door, to try to slide the iron plate, or to continue north up the tunnel.</em>