Related Clues:

• ''On the double!''
• Posthaste, briefly
• ASAP
• Letters akin to P.D.Q.
• 'Stat'
• En masse
• A.S.A.P.
• In very short order
• Express letters?
• Simultaneously
• ''... and make it fast!''
• 'Stat' in memos
• 'Yesterday!'
• Order request
• 'Quick!'