Map: Skyline CTF Doubles (Halo 4)
is the most ideal map. it usually appears in the 3rd map slot.
When the match starts send the main player who is earning the medals to the enemy flag pick it up then head to the middle and wait at the top of the lift.
With the player on your not getting CTF medals have him run to the lift nearest your spawn and go up backwards. have the person earning medals Assassinate the enemy while holding the flag to earn two CTF medals per kill.
-Assassination (doesn't count)
If this is being done in split screen usually i would use my 2nd controller and do all of the running then press
on my main when i saw a back faced to me.
With this method you can get 125 medals per game if your are efficient
Search for Team doubles as this is the only mode with CTF and KOTH
This is halo 4 remember to equip Mobility under the customisation menu to increase run times on both the dummy and your main account also if both enemy teams are holding the flag when the timer runs out the game will extend by 2mins once.
Half credit to Games Master and Jendorf for helping me find this.