Medal of Honor Easter Egg - Poster References

1. Go on online multiplayer, any game mode.

2. Play on the Marketplace level.

3. Scattered about the level on the walls are some half-ripped posters, one showing a grenade with a smiley-face pin, the other showing free runner Faith.

The grenade is a reference to Battlefield Bad Company 1 which used the same grenade as its logo.
Faith is from the game Mirrors Edge.
Both EA games and DICE are connected with Medal of Honor, Mirrors Edge and Battlefield.