I think that the song is all about the fact that when they were younger, they would just play pretend (katniss and gale) but now, they are in the real world, kept strictly under the capitol, and that when katniss has stepped forward with peeta, that from that point on, they wouldn't have a second alone, even when they were sleeping, they had to keep there eyes open, to watch out for the capitol, and any tricks they would try to pull to twist the arena and the game around! Eventually, katniss learns to properly hunt, and to always be on guard, watching out for traps, but saying that everyone is waiting for you to breakdown, and that you have to keep your eyes open to avoid being caught, especially after the games, when everybody is out to get her.