The two videos below are very interesting. The first isn't a Roslyn Walker performance. It is, however, a clip from the TV special When Magic Tricks Go Wrong, which aired on Channel 4 here in the UK. In this clip you'll see a stunt involving a nail and some plastic cups not quite going to plan.

In the second video you'll see Roslyn Walker perform his version of this stunt, but rather than a scrawny little nail he uses a 4 inch spike!!