Not sure if this is a bug.
I know its realistic in a way, that something would stop a door from closing but in game it seemed to stop progress. I think it was a door that had to close for something else to happen or you had to be able to open it.(I can’t remember now) I was stuck after this happened and had to reload just before it happened and then I was able to move on and re-open the door.
https://steamcommunity.com/sharedfiles/filedetails/?id=96487653
Cheers
It’s possible to progress at that place without having this door close (just shoot the hell out of the scientist who normally runs into the sensor mine trap if you don’t kill him). And you should be able to open up this door by breaking glass and pushing the fire alarm button. In case it don’t work if the door is blocked by the sentry gun - that’s definitely a bug.
I had this twice and assumed it was a bug, but I was still able to make progress another way. Now I can’t think how I did it.
Edit: I used the conveyor belts going the opposite direction.
Founded in 2004, Leakfree.org became one of the first online communities dedicated to Valve’s Source engine development. It is more famously known for the formation of Black Mesa: Source under the 'Leakfree Modification Team' handle in September 2004.