http://en.wikipedia.org/wiki/Cold_welding
Learned about this the hard way, doing exactly the same as you. Ended up bolting the tool into the BB, putting that in a vice, and having two people swinging on the frame to get the BB out.
Soak it in release agent, bit of heat (small blowtorch), then try again, if you're lucky it'll scrap the BB but the frame will be ok... I wasn't so lucky!