1. Frodo is looking towards Cirith Ungol - Shelob is above and behind him
2. Frodo looks behind him... away from Cirith Ungol. Behind Frodo you can see the steps and Shelob's stinger
3. Frodo looks back towards the steps and Cirith Ungol (you can just see the tower). Shelob has whisked herself back up.
4. But back down she comes.
5. You can see Frodo's head start to go back in a whiplash motion.
6. more of the whiplash motion is evident.
7. The camera cuts quickly to Frodo's face... the head continues back in the whiplashmotion.