Why would we "evolve" unconsciousness after a heart attack?

Just thought of an awesome anti-evolution logical argument: Unconsciousness after a heart attack. How and why would that have ever evolved?

Would you rather spend your last thirty seconds of life being able to grab a coworker and say, "My heart just stopped. Tell my wife I love her, tell my parents thanks for everything, tell my kids I'm proud of them, and that I'll see them in heaven. Oh, and thanks for standing by me at work."

Or would you rather your brain shut down to conserve energy and last an extra three to five minutes? For all of human history, that "feature" did no good. Until now, when we have the medical ability to dissolve the clot and restart the heart.

Thoughts?