iron will sometimes does not working.
Stridor negates it, which is one possible explanation.
When I play with the survivor side ,I heard moans.
Is it a specification?
If Stridor is in play, I believe you will hear your moans through Iron Will, yes. The killer certainly does.
Depends onthe level of your Iron Will, only lv3 will make you 100% quiet. And as other said, the killer might have Stridor, which makes Iron Will pretty useless if the killer has good ears