I used to have the problem of startling myself when images became 3D too, have nearly gotten over it.

The key is to trick your mind that you're not paying attention to it, otherwise it'll probably just vanish and you'll wake yourself up enough to need to relax for another good 10 minutes (not fun if this happens again and again, gets really annoying and frustrating.)

Btw, I really don't understand people that think paralysis is freaky, I enjoy the feeling, its very calming, feels like floating down a gentle stream of water on your back. It will make things very relaxing if you visualize this while trying to wake induce, might help with the 3D startling you're experiencing.

To me when I start to see visuals, it's like the feeling from standing up too fast, the vision becomes all brown-yellow colored with strange shapes and patterns, then eventually from the inside outwards it resolves and I can see again (into a dream if I'm wilding). Really amazing experience.

Just remember, when it feels like you're being "pulled in" (you'll definitely know what I'm talking about) ignore the feeling, don't think about how your body is feeling or anything like that, don't think something to yourself like "wow this feels weird", just let it take you.

Good luck people