Visible crew/equipment: When Memphis (Nicolas Cage) is speeding up to take the final jump on the bridge, you can see the camera crew on the other side of the road filming, if you look closely you can make out the shading devices used exclusively to block out the sun from the camera. Look to the left of the jump just before he hits it. (01:39:30)
Visible crew/equipment: In the "Director's Cut" version, when Memphis makes the impossible jump over the accident on the bridge, you can see the fixed camera inside the car when it first hits the bridge deck, but it mysteriously disappears after that. (01:49:05)
Answer: He sits on his hand until it goes numb, and then masturbates. "Stranger" refers to the fact that it feels like someone else is doing the work for you.
Nick N.