Metal Gear Solid 4 — Snake/Raiden scene in the Nomad prior to Shadow Moses

Question

1.) In this scene from MGS4 (the Mission Briefing just before the Shadow Moses act) around the 3:05 mark Raiden says:

I won't live a proxy life, a slave to someone else's will.

Snake then replies:

I'm a shadow, one that no light will shine on. As long as you follow me, you'll never see the day.

Is it just me or is there a huge disconnect between these two lines? Is this just bad writing? Or if not why did Snake reply the way he did? What could he possibly mean?

2.) Furthermore at the 3:50 mark Raiden says something interesting:

But once this is over, we will have our freedom. I'll release you, it's the only way I'll ever be free.

Snake then replies:

Raiden, five years ago, that's not what I meant...

What did Snake say five years ago in the Big Shell incident? If I remember correctly he said something about finding something to believe in, but this couldn't be what he was referring to? What was Snake referring to when he said the above? And why would "releasing" Snake free Raiden?

Edit: why did someone remove the MGS series tag? This question is primarily about MGS4 but it also references the older MGS games, and in particular, asks about events in MGS2. Please read the entire question before editing needlessly next time, thanks.

Answer 1

1: Raiden is asking to follow Snake in his crusade against Liquid. Snake is trying to dissuade him. The arguments aren't answers to one another, that is why they seems to cut.
Raiden is saying he won't live as a pawn, as he lived since MGS2 (and lived in MGS2). Snake's answer is that he shouldn't follow his example by becoming a shadow.

2: While I can't find the exact line, the theme of MGS2 was that Raiden was just a pawn in the hand of something/someone, just as Snake was in MGS1 (and 2 for that matter, just a conscious pawn). At the time of MGS4, they finally know who were pulling the string, and are trying to bring him down.
By freeing, Raiden means finding Liquid and eliminating him, making Snake free of his manipulation. To which Snake answer that when he revealed Raiden was a pawn, it wasn't to push Raiden to follow him, but to go live a normal life (with Rose), he also repeat that argument just after.