not sure if you know this. But it is pretty common practice for deathrun regulars to allow other players to finish the course before pressing the button to force everyone off.
Since they do it so fast it is common for non experienced players to ever make it to the end. In general I found alot of them do it out of kindness but you may be wrong in this case I was not on.
But with 5 players remaining and only 2 at the front they are not delaying the round from all players active on the map.