Possible Clues:

• Mutual
• Right police car crashes into convertible
• One of two is half expressing mutual relationship
• Going both ways
• 1/x is the ____ of x
• Turns up, the foreign army unit isn't finished getting diamonds at the end of the war - and the feeling is mutual
• Mutual respect's beginning with police car going off
• Done in return
• Cross cool redhead over mate pinching fabulous bird
• Mutual friend's second police car wrecked