So, in a generation that might be the final generation (but might not), the player who is in third place is supposed to continue playing, but not use his heat or plants or money in an attempt to maximize his own score?
That seems like a difficult stance to defend.
"I lost because the player in 3rd place kept playing instead of passing" is weak. It's a cop-out way of saying, "I played poorly because I put myself in a position where I win only if the game goes 10 generations even though it was obviously going to end on generation 9 given everyone's plants, heat, and other resources and actins available."