Refusing to speak to the police or otherwise being evasive is not the same as exercising your rights. Your behavior prior to requesting an attorney can be used

Refusing to speak to the police or otherwise being evasive is not the same as exercising your rights. Your behavior prior to requesting an attorney can be used against you--"he was acting suspicious by not giving me direct answers". But you can't request an attorney unless you've been detained, which they won't do. I don't think there's any substitute for (a) being polite ("Yes, sir. No, sir.") and (b) being aware of the context. Obviously you should never consent to a search or even give the impression that you're consenting. But literally not talking to the police is not really possible, so there's no avoiding keeping your wits about you so you can act in the most appropriate way possible. Pulling out your camera is a pretty ballsy move that could escalate things, but I wasn't there so can't judge. But if there were witnesses watching such as other passengers or, especially, a conductor, I wouldn't risk it. I'd just ask for the witnesses' contact information afterward. An irate cop could always snatch your phone away; it's much harder to intimidate a witness, and anyone inclined to do that probably wouldn't think twice about taking your phone or doing something worse later, anyhow. Ultimately you're pretty much helpless, so you have to optimize for the [more likely case] of the cops being mostly honest. They're unfortunately trained to intimidate (we've militarized our civilian police forces), so just because they're acting like assholes doesn't mean they're actually assholes.