Do you really want to open that door

[pelmet]

Remember being told on one of the turboprops I flew, to never open the door while an engine run is being or really after engine start unless you were 1000% sure it had no pressurization such as a window open, etc. The same can be said if the APU is running. If you have to open the door when all doors and windows are closed, you may want to be standing as clear as possible.

https://aviation-safety.net/wikibase/wiki.php?id=203827

I see that it is snowy where this incident happened. Sometimes in cold weather ops, the outflow valve is manually closed for reasons such as preventing blowing snow from entering. That can lead to other problems.

[Rowdy]

pelmet, generally the outflow valve is on a bulkhead, within the fuselage on the pressure vessel. Not on the outside of the airframe. Unlikely to have to worry about snow.

We run engines with the doors open. I've done it in many pressurized turboprops. Generally the bleeds are off. However, while lacking an APU, the bleeds can be run for the pacs and some heat or cooling on the ground.

Many times the passenger door is opened with the #2 engine still running. Many safeties in place for such things.

We are however warned about the door when an external air cart is being used as it can slightly pressurize the cabin.

[Zaibatsu]

Most larger and higher flying planes, including the Gulfstream and nearly every jet airliner, have external outflow valves. There’s simply no other way to get that much air out of the aircraft.