Any question answered...

This is a bit tricky because the chainring stops the bb from being able to rest on the floor. But the key there is probably the hench-person. Maybe the builders would like to help?

Does the poor bike have a pair of wheels on it?

Try this:

• Fit wheels to bike
  
• Take bike into street
  
• Rest opposite pedal on the curb so that when you turn the bolt in the desired direction the pedal fouls the curb, preventing the crank from rotating
  
• Attach cheater bar / wrench / whatever
  
• Hold bike down firmly by saddle / bars / top-tube with both hands
  
• Use foot to repeatidly stamp down on cheater in desired direction