how do you think it will be very close to you, in the dark, in an enclosed room????
Same as any centerfire cartridge, regardless of barrel length,
in an enclosed room. If it's life or death, 1- you probably won't notice it, 2- it's always better to be alive and deaf than to be dead.
IMHO, if it's a range gun you'll probably be wearing protection anyway, and you'll probably be able to shoot (and enjoy) it more. If it's a hunting gun, one or two shots in the wide open won't bother
you that much. If it's a SD gun, if the porting helps you to practice with it more, you're more likely to come out of a situation alive. So go for it if you want to.
Just for the record, the only ported gun I have is a Sporting Clays shotgun that is only available in a ported barrel.
I do have ported chokes, I can't tell any difference, positive or negative, with them.
Wyman