Track Etiquette

If you think that the rider 3 is moving out you will automatically move outwards as you come over the top of them. If youre getting it right (when racing not training) you will be "rushing" up to number three anyway and its really the responsibility iof rider 5 to move around you. In time you will know where you are in the bunch anyway.

Best rule of the thumb is dont make sharp moves until you are experienced and NEVER over lap the wheel in front..

V

I have relatively little experience on the track, so I want to learn the correct and safe ettiquette of riding in a group thoroughly. I've noticed in the intermediates at Herne Hill people are often all over the place, moving without looking etc.
I have a very basic question about the scenario below which I found myself in, I wanted to know the correct way to deal with it.

It's the final sprint of a race. Riders 1 & 2 are traveling along side each other. I am at the back and intend to move past all three. I move up along the outside, but as I approach rider 3, he moves out to accelerate past 1 & 2. I am already traveling faster than him and don't have time to look back over my shoulder.
I don't want to slow down and lose my speed, but cannot be sure I won't be moving across someone's path if I pull out further.
Where should I have been and what would be the correct way to deal with this?
Should I be allowing enough space when I innitially pull out to accomodate no. 3's move?