After looking at step 5's image and analysing the wiring I discovered that it is not a transistor. A transistor would light the LED up when you touch the wire in it's base, not turn it off. Basicly what you do is to create a short between the + and the - when you touch the wire, bypassing the LED (electricity takes the least resistance path, in this case the wire, and when the wire is not connected the LED) and turning it off.