ATSKNF and No retreat wounds

[Mr_I_am_Hungry]

Really new to the game, so be nice. I'm trying to determine when Space marines take No Retreat wounds after an assault. So I lose assault with my marines. Now what I think happens is

 

1. I make a leadership test, I fail and have to fall back

2. I make a initiative test

3. I lose test, I take wounds, I stay locked

 

Now assume that the thing I'm locked with can't sweeping advance. Do I just escape? I think I do, but I'm not sure. Do I always take No Retreat wounds no matter what? I would really appreciate someone breaking this down for me. Thank you all.

[Frosty the Pyro]

you will only take no retreat wounds if the enemy makes a succesfully makes a sweeping advance. If they fail their sweeping advance or are unable to do so (aka terminators or gargantuan creatures) then you escape and are falling back. Remember as marines you will automaticly rally so long as no enemies are within 6"

[Mr_I_am_Hungry]

Thank you. That's what I thought, but I just played a game against a friends nid army and neither one of us was sure, so I took wounds after every combat I lost. Made combat really short... For some reason I seem to have lost that game...