Of all of the catch-phrases I hear uttered from job seekers and hiring managers, "interviewing is a two-way street" is the craziest. Interviewing for a job is not a two-way street.
Yes, while the interviewer is trying to determine if you will be a good fit for the company, you should be evaluating the company. Do you believe you can work for this manager? Can you picture yourself working there?
Saying that the process is a two-way street, however, implies that both parties (the one that wants the job and the one that has the job to give) have equal power. While you can decide to step out of the running, only the manager can say yes. That gives the edge to the manager.
As a candidate, you still want to assess the company and the manager. But, don't go in to the interview thinking you have the same power as the person interviewing you.