Sorry to say but the chances are too low....please dont try your luck by not taking the second dose....because it will be more dangerous if left in the middle, dangerous for you as well as for the baby . Let me explain you, if you have not yet aborted  you will let it grow inside you, pregnancy test coming positive will excite you of being pregnant ....but the reality is till 3 months you don't know weather it is really alive or not,  healthy or not,  sonography doesn't show heartbeat in first 2 months and when you realize that its not healthy and has some damage within it will be too late for it to abort....and too much dangerous for mother if it is dead and was inside till 2 months....