The Dvali Safehouse is just next door to the Red Queen. There are a few ways in. Some of them depend on the augments or items you have. You could want the Rebreather, Hi Jump or a few Biocells. Most will find it easiest to slip in using the nearby sewers or that side of the Dvali complex. Head to the Southeast from the Red Queen. Go down the alleyway past the Irish Stool. Either hop of the fence or hack through the gate using the nearby Terminal.
Going this way, go to the lift under the balcony of the Eastern balcony. Interact with it to and use a Biocell to raise it up. This makes getting in easier and it gives you an escape route with your target.
Inside the Dvali Stronghold you have a lot to avoid while in there. Go through the door in front of you into the kitchen with 2 Dvali Henchmen. They are talking and are easily distracted if you throw something past them. You can also wait for them to finish talking. One of them will go into the bathroom. This gives you an easy opening for you to quickly take him down. Slip back into the kitchen after that and take down the other Henchman. Drag the body into the bathroom to hide it away so it will not be discovered later.
Go to the Northeastern door in the kitchen and head on out of it. This area is under heavy surveillance. This will make it difficult to get around until you Find the Control Room and disable the cameras. Head to the Eastern corner of the short wall.
There will a set of stairs behind you, If you have Remote Hacking or the cloaking augment, then this is the path for you. Take them up and you will be heading for the top floor. Stop at the top of the stairs before the first landing. Either activate your cloaking or disable the camera using the Remote Hacking. EMP grenades or rounds will also help a lot here as well.
Go to the next corner past the camera. You will see a Dvali Henchman patrolling this area. Wait for him to have his back to you then take him out or shoot him. Now, there is door on the Northern side of this building. You can grab the Henchman you just dealt with and drag him to the door. The door is locked. It has a Security Rating of 3. You can either hack in or use the code 0666 to get inside. Drag the body inside and close the door.
Inside this apartment, go to the far side of the entertainment center, closest to the large speaker. Look at the top shelf of the entertainment center itself. You will see an eBook. Crouch and look at the top left portion of that shelf. You will find a button you can press. Do so and turn around to find the control room itself.
Head inside the control room. Go to the Security Laptop in the back right and interact with it. It has a Security Rating of 3. Be ready for some hacking or have a Multi-Tool on hand. Inside the terminal, go into the cameras and then alarms and disable them all.