[Does so]

Once there was a shotgun made that had its "business end" flattened to spread the shot. As I recall, it didn't work all that well, but it might be worth a try for that hallway.

[Tijeras_Slim]

There was a device called a “duckbill spreader” that was used by SEALS in Vietnam that flattened out the pattern. A modern version is in production that can be screwed in like a choke tube (if it’s made to fit your gun).