I never thought of driving into the canyon from the top. That would, indeed, be a daft thing to do. The danger I was thinking of was when the good guys ride up the canyon floor to try and find the cattle that the bad guys have rustled.

I like meself's explanation better -

    If I let my best companion       =       If I let my best friend                                 
    Drive me right into the canyon       Drive me right round the bend


DC