Retreat and Escape
The whole purpose of using a defense spray is to stop your assailant immediately, disable him so he can no longer hurt you, and give you the opportunity to escape to a safe place. DO NOT attempt to hold the assailant for the police. In fact, get as far away from him as you can. DO NOT move toward the assailant in any way since you could be affected by the pepper spray, which then could incapacitate you. The best way to escape is by backing away from the assailant as you're shooting, or immediately after.
Do not turn your back on him! Obviously, you need to see where you're going, but don't turn your back and run away until you're at a good distance and the assailant no longer presents an immediate threat. If the assailant attempts to follow you or the first spray wasn't enough, you must be ready to spray him again. Once you're a safe distance from the assailant, turn and run quickly to the nearest safe place, preferably one with people who can help you. Once you reach a safe place, be forceful in your request for help. A command of, "Call the Police now!" will usually do it since people can sometimes be hesitant to help or get involved. DO NOT WAIT! And do not go back to where you left the assailant. He may still be in the area.