Narrative:

Main cabin door was secured; APU running and supplying bleed air to the cabin. Approximately 30 seconds after the door was secured the aircraft started to pressurize while on the ground. Other pilot opened door from the outside (he had just departed the aircraft; but had forgotten his water and was returning for it) and it immediately blew open narrowly missing his head. Force was strong enough to rip both telescoping rods from their attachment to the door.

Google
 

Original NASA ASRS Text

Title: CE680 Captain reports cabin door being opened from the outside with the aircraft slightly pressurized. Door suspension is damaged and injury narrowly avoided.

Narrative: Main cabin door was secured; APU running and supplying bleed air to the cabin. Approximately 30 seconds after the door was secured the aircraft started to pressurize while on the ground. Other pilot opened door from the outside (he had just departed the aircraft; but had forgotten his water and was returning for it) and it immediately blew open narrowly missing his head. Force was strong enough to rip both telescoping rods from their attachment to the door.

Data retrieved from NASA's ASRS site as of April 2012 and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.