His ability to play act is actually super terrible! But he can be genuinely stealthy (Ninja, yo!) and he might be able to pick up enough of the native mannerisms that, if he hides his body and chin somehow, he can at least merge with a crowd.

After his upgrade he can also brainjack other machines and control them either by wiring himself to a control port or running his sword through an AI core...not sure how that would come up but that's a thing.

Edit: Also worth mentioning, in terms of info he gathers-Raiden is a military cyborg which means he has a data chip embedded in his left arm. Anything he perceives with his senses is recorded on this chip-Everything he sees and hears and smells and touches. He can turn this off sometimes but he will have this functional while on duty out there, in case anything happens. Baaasically, he's a walking, talking Google Glass.