Happened to me a few times in the H300C while on photography flights.
I always fly with one door off during photography flights, two doors off isn't a good idea up here in the cold.
Once with the right door removed and slipping to the right at 35-40kts with a lot of boot on the left pedal and the photographer hanging out the right side, a remarkably heavy wind entered the cabin and blew the left door open. Things started flying around inside the helicopter and to my amazement I lost visual for a second and felt pain in my eyes. Later I realized that the sand from the carpets got sucked out of the carpets and blown into my eyes. It was kind of scary but I kept my cool and looked like the trained professional that I am and was expecting this to happen, until the sand cleared from my eyes. (Had the dark visors on)
It's amazing how much sand the carpets can absorb and this sure taught me to tell the engineer to thorughly clean the carpets at regular intervals!
On another flight, I was flying an aerial ad filming and during one of the approaches to the target the darn left door blew open. Some of the video tapes that the photographer had put on the floor, with some great shots on of course,
started sliding over the floor of the helicopter and almost managed to sneak out the door. But with my rattlesnake reactions I managed to grab them and bring'em to safety. I have to say that before I reached for the tapes, I had assured myself that it would be better to do that in stead of taking the risk of having them flying out of the helicopter and falling onto the heads of innocent people on the ground that were watching a beautifully flown helicopter up there.
When things like these happen you think, damn it's good to have a strong ticker.