Well they can certainly confirm how long there is brain activity, so the seven minutes is likely good. And they can tell what part of the brain is active, so they could say with relative certainty that it's memories. But the "reviewing your life" thing is just a guess. You could be replaying that really embarrassing moment in seventh grade in slo-mo for all they know.
I'm calling BS. Though, I think whether this is true or not is unimportant. If when we do die, our life flashes before us for 7 minutes, then we sure as hell better make it a good 7 mins.
Call me weird or anything, but I have had similar thoughts like that... Just imagine, your life right now is a dream, you wake up, and you're in your back in your second grade classroom, realizing you just woke up from a short snooze...
They are saying that because after cardiac/ respiratory function stops the brain can last up to ten minutes before serious damage occurs after seven minutes the brain is likely starting to shut down.
If you were, theoretically, in those last seven minutes of brain activity right now, then yes. You would still die in the exact same way, because you don't remember how you died, and thus cannot avoid it. If you were to learn of these seven minutes and try to evade your demise, then it happened in your real life, and you die the same way. It is unavoidable.
...I'm sorry for whatever I did wrong, however minuscule it is.