Pretty sure that's for the torpedo tubes.
The doors that Tam is talking about, are not for torpedo tubes.
The torpedo tubes on 052D have a door that "slide open" to the side rather than "fold open" upwards, and are positioned slightly more forward of that location.
Don't want to sound like a jerk, but can you show me a picture of it ? Because I only see two doors, this one and the bay for the RHIB.