Interesting thought... but wouldn't your body already have the same speed and direction as before the switch-off? The switch-off would only stop external forces from altering your speed and direction. So I would estimate that you have plenty of time to steer clear of stuff after you turned off the gravity effect. It kind of similar to switching off the autopilot in an airplane. After doing so you have to take manually control of your position in space, but you don't instantaneously stop flying.