Still more question about Inception?

Fishers mind had security. Meaning, his subconscience was trained to attack anything foreign. This is what was happening in the first layer. However, it takes a little time for the security to pick up on the foreigners and to act on it. This is why they had some time in the second layer. Those were just normal projections that kept looking at them when Fisher was learning it was a dream. Third layer, it was like security kicked in super drive because of the secrets on that layer. The whole movie is a little mixed up though. They don't always follow through with the rules of the dreaming. I hope this helped though.