Answer:
I would go for the one person, but not because I'd rather risk one life over five.
Explanation:
But instead, I think it would be a lot easier to warn the one person to move out the way of the trolly, than to try and get the attention of five different strangers on the other track.
Not to mention there'd be much less confusion and chaos, if you just signal to your friend to get out the way, because you only need that one person to hear you.
I hope you like my answer :)