buzz lightyear on level 4 - throw cube at the red squares on the wall (where all the red, explosive drums lay around...very close to second BnL cube station as well), which will turn white once hit. timing is key. hitting the square will "open the gate" allowing the "electron" to pass through. Once it passes through each of the squares/gates it will expose buzz.
Does anyone know how to open the elevator door on this level (that is near the wall where buzz can be obtained)?