Instructions
Use the spaceship to travel to the "Mordred's Secret Hideout" area.
Pull the lever in the library, located in "Mordered's Secret Hideout."
Push on the wall to the far left. Pushing on the wall causes it to break, revealing a path.
Proceed through the opened path, and enter the circular area. A robot appears.
Wait for the robot to be destroyed. The robot self-destructs automatically. When he self-destructs, he drops the green tube. Use Merlin the mechanical owl to pick up the tube.