At 10 feet, you conduct a visual "risk and threat assessment" of your area and people in it. In this assessment, you develop an exit plan, identifying your escape routes (never place yourself in a situation you cannot see yourself getting out of). These escape routes can be other windows in the room, stairs, a ladder, or the door you walked into. All of your escape options need to be both within your physical and emotional limitations.
If you do not feel the area is safe, develop exit strategies. An exit strategy is a way to physically avoid contact with a possible threat or dangerous situation by leaving the immediate area. If there are no immediate escape routes, identify positions of cover, or barriers, you can place between you and a threat, especially when a weapon is present.
The last thing in your "risk assessment" is to identify weapons of opportunity and weapons of availability. Weapons of opportunity are weapons you have on your person, like a concealed firearm, a knife, or even a tactical pen. Weapons of availability are items in your immediate area you can use to physically defend yourself. Always remember if such weapons are present they are available to both you and others.
Getting Closer
At distances of 10 feet, respect for "proxemics" plays a role in safety before you contact someone. As a person approaches you, give the one-handed "halt" sign to alert the person you are aware of their presence and to ask them to respect your boundary.