Honestly some wouldn't even spawn the boss if it weren't for the others killing some mobs while they sprint past everything. On lower levels I found a newbie (green luck), non-ss warrior doing it alone. He didn't kill any minion. I caught up, the boss wasn't there, I asked why. He said he didn't know.

But as far as I can tell you still get the points and the drops even if you're at the beginning of the map, so it's no issue. I had it happen once when I was in the big trunk area; I still got the drops, I wasn't looking at my points but I'm pretty sure sure they were added.