Just tried it and the new activity resets the flow, and that last activity wins, in that it is the one you end up with at the end. I think this makes sense in that we need to let the last one win. Trying to preserve any intermediate state though would be difficult. In practice though I think the only state we would lose would be the "New Account" screen, which is the start of the flow anyway. Once credentials are typed in, the setup process is pretty fluid from there.