Destiny icons and symbols

Question

In Destiny, I have come across a few different things which I would like to have some conformation on.

1. Firstly, often times when I am sprinting, there is a purplish glow around my character that appears to be wind, but some conformation would be nice.
2. Secondly, when I am being shot at from behind, I occasionally see large red objects, that look a bit like arrows, but I can't be sure.
3. Finally, when I point my weapon at a person on my team in the Crucible without aiming, my hip sight often turns green, or green x's appear. If I do this to an enemy the sight turns red. Does shooting someone on my team when the sight is green have some kind of healing property?

Answer 1

For your first question, as I am unsure of which class you are playing as this is only a guess. I believe if you are playing as the titan (striker subclass) you could be experiencing the effects of either the Shoulder charge or Juggernaut perks. After sprinting for a set distance you will see particle effects surrounding your character.

For your second question, these are most likely going to be damage indicators. These will show you the direction that you are receiving damage from.

And finally for your last question, no, your gun will not heal your team mates. this is simply a visual indication of whether the guardian you are aiming at is from your team (green icon) or the enemy team (red icon).