Terra Prime game end condition

I think I'm having an idea about the game end trigger in Terra Prime...

Instead of each player having a game end timer (the number of player tokens they have to put on the board), perhaps there should be an aggregate timer. Each time a player takes a scoring opportunity (completes a Demand tile, Kills an Alien, or places a Colony), they could draw a tile from a preset pool of face down tiles. there would be a set number of Green, Yellow, and Red tiles. The green tiles would be worth maybe 0-1 VP, yellow worth 1-3 or something, and red worth 3-5 maybe. In addition, maybe 3 of a total of 5 red tiles would say "End" on them, and the game is over when the 2nd "End" tile is drawn. This way there's a little uncertainty in exactly when the game will end, there's a race element for scoring opportunities, and whenever you make a scoring play, you literally hasten the game end.

Some potential problems with this is that it might create a game of chicken because taking the last tile of a color makes the next scoring opportunity worth more points. That suggests perhaps the VP value should be reversed, or that some other benefit should be awarded with the Green tiles... potentially a free module (gun or shield in Green, cargo in yellow perhaps) or coins.

On the up-side, this could facilitate some additional story arc in the game. Maybe when the Green pool runs out, all players get 1 additional action per turn, and then again when the Yellow pool runs out. This would basically mean that in the late game, when trips around the board are longer, all players would move farther each turn. Thematically, well I can't really think of a good thematic reason for that. maybe as time goes on, the Federation learns how to be more fuel efficient or something. Who knows.

An interesting afterthought - in the case where green tiles confer a free module, that could serve to differentiate players. I could see the game giving players 2/3/4 actions per turn in the Green/Yellow/Red phases (respectively), so long as during setup players begin with a Colony marker on their ship (which is basically the first action you take anyway). The Green pool could be 1 tile per player, and the rewards could be cost balanced: 1 Gun, 1 Shield (no energy, or maybe 1 energy), 1 Cargo hold, 1 Credit (or maybe 1 Brownium), 2vp (worth more than 1 Credit but less flexible). The Yellow pool could be 2 (3?) tiles per player (or maybe just 9 tiles) with rewards of 2-4 vp. Then there could be 5 Red tiles worth 4-6 VP, 3 of which say "End" on them. I'm not sure if the vps I've mentioned for yellow and red phases should be reversed or not. I keep going back and forth on it.

Anyway, this sounds good at first blush. I will mull it over and maybe make the tiles to try it out.