Sometimes you can't prevent for the HH (noise and pictures) to end. But you can just continue doing what you were doing and you should be back to them soon. Don't get excited, stay calm, observe passively, don't even think about them, just watch. You were close.

Sometimes you get only pictures, or only noise, or only sensations of movement, or vibrations. Next time, when they stop, yu can try to do a motionless RC - tell yourself "If this is a dream, I'm floating". If you start floating, you know you are dreaming and you can stand up and have fun in your lucid. If not, just keep going and try RC again little later.

Here is more about sensations and types of entry into WILD.