Let's try to keep things in perspective people. I don't care what Gin does one way or another, I have no particular feelings towards him but I do care about the writing intelligence (Just saying lLAlalalalaLALAaa to Kanonji).
If, IF Gin were to even THINK about choosing tits over god-Sama, I really doubt he would have done it then and there. Just think about it. For one thing he's Aizen's RIGHT HAND for God's sake, I'm pretty sure Gin knows what he'd be dealing with. It' arguable that no one so far could know Aizen better than he. The comment Aizen made about him being a "funny kid"? Which theory is more likely? 1. Aizen knew Gin was about to betray him (obv. didn't happen, and it would be waaay too simple and predictable)
2. Aizen (in his supreme disproportionate omnipotence) thought Gin was funny because Gin still thinks he's fooling him. Meaning that Gin intentionally stabbed Rangiku with a non-mortal blow to thrown Aizen off the trail, whilst waiting for a better opportunity, or even to fulfill a much bigger scheme.
Now this is just a theory, but I am in school for screenwriting/filmmaking. And assuming the writer of a story retains some semblance of intelligence, the seemingly out-of-place holes in this chapter could easily make perfect sense just a few chapters from now.
Gin's lack of speech and abrupt attack completely fall in line with an antihero or counter-conspirator's psyche. Once again, I couldn't care less, but I'm sick of people trying to figure out the entire future of the series based on one drop in the ocean. THINK.
Now it could be that or many other things, but my point is it's too early to declare what's what with Gin. And I doubt a bunch of fanbois/gurls are noticing all these plot holes that Kubo, Shonen and Japan missed.