it's not that you're guaranteed the job, they're just interviews.
hype is that if you qualify for a 2nd interview, it means they're going to take you, not always true.
it's not the rank, it's the types of questions they ask, and how you respond to them, and if they "like" what they want to hear, and also if they "like" you.
example: can you work on sundays?
answer: no
reason for the "now hiring sign" (we need sunday workers)
once you tell them you can't work on sundays, even if they do a second interview, there is almost no way you're getting in. they will talk and talk because they can and want to, but just because of that, you will still be told they will "CALL YOU" ... and instead of giving them a call back from your cell phone, you could decide to just visit them in person, to get a direct answer. and if they say they need sunday workers, you don't want to do it, then you're not qualified. either way, second interviews might follow up with drug testing or not, however doesn't mean you're going to score a job.
reason why you apply for multiple jobs and not get too comfortable just because you dressed your best to two consecutive interviews in a row at three different jobs.
life is life, good luck.
oh yeah, a job's a job.