A confirmed spoiler already huh? Its sounds nice, I do agree with POW that Gin moving the conversation between him and Rangiku away from Aizen can mean that he has something to hide. But Rangiku collapsing probably doesn't mean Gin stabbed but maybe because of the injuries she already has.
Your kidding right? If you had read the last chapter or the one before that or early, early bleach chapters then you would have known that he's one of Ichigo's friends.
SICKKKK Avatar ? kenpachi owns all he is just bullshitin with us he is like a god he just does not know it yet