1-1. Get yourself a rifle with Optics;
1-2. Try aim down the telescope and walk\run\spring\reloading
2-1. Aim down with the Dot or Iron sight;
2-2. Try crawling while aimming down, see how awkward the view is.
3-1. Get a rifle with grenade luncher;
3-2. Aim down the luncher,and then reload the luncher;
3-3. Your eyes even fly into your body!
4-1. While not been a Diver,Get any rifle and aim down with dot or iron sight;
4-2. Go to swim, notice the rifle automaticly swap to your back when in to deep water.
4-3. Try aim down,you'll find you eyes fly to your back and viewing the sight!