I haven't read any theories about Amuro yet. But, my assumption about him is like this. BTW, I'm with the Bourbon=Scar Akai=Amuro Tooru theory.
After Amuro completed his study and training in the police academy, he is on his way to become an officer. But an unexpected, tragic event that involved Akai (and another character that is special to Amuro and Akai might have offended/encountered) could have changed the decision of Amuro, choosing to join the Black Organization. I assume that my theory is plausible with the event happening after Akai, who disguised as Moroboshi Dai, was exposed to be an FBI agent infiltrating the BO. If Amuro wants to get revenge on Akai, it is possible that he will join BO and kill him.
Although some plot holes in my theory are why is the need for Amuro to join BO just to exact revenge with Akai and who is the character that might be involved in their 'rivalry'.
This tactic would be very dangerous for him and has a high chance of failure. Why would he reveal himself to the BO and wink at Chianti, who has a sniper pointed at him already. If he's confident that BO won't make a scene in a public place such a mall, wouldn't he have thought the possibility of him being tracked by the BO with his disguise?
It's just a very dangerous and high-risk tactice for him.
A major hole I see in this is that BO is still unknown to the Japanese police, as what Gosho is portraying throughout the series, AS OF NOW. No signs that the Japanese police is aware of BO's existence. So, why would the police benefit from stopping Bourbon? He's just a new member of the BO. The only thing that could make the BO wary is the fact that Bourbon could reveal to the police the motives and objectives of the org, if ever he's captured alive.
P.S. SORRY for butting in to you and Chek's conversation. :-D