Emergency use is exactly what it is for. It does work. At first I thought it didn't. It works off a clutch system like the CVT. the motor spins then you have to push/hit the impact and clutch engages to knock it loose. Do this several times and wah-lah
I found a video of one just like it.
http://www.youtube.com/watch?v=tV0GhvbALaA
oh, I agree air tools are best.