Metal Gear Solid: Portable Ops Plus

Enter the password in the "Recruit" "Password" section of the main ingame menu.

Password - Result

TTOGZWSREYD - Arms Magazine Soldier

Enter the password in the "Recruit" "Password" section of the main ingame menu.

If you find yourself in trouble or just on a special mission with either a constant Alert phase or a neutralize enemies objective, throw them down and point the gun at them to make them "Freeze". This will force them to go into the ground hold up position. This approach is recommended, as you do not need lots bullets to force your way through the stage. Also, if the Alert phase clears you can see how many stars the soldier has to deem whether or not you wish to recruit them to your cause. From there you can leave them and continue, knock them out for items, recruit, or try the next trick. Note: A stage can only play host to a certain number of soldiers; if all the soldiers stationed there are alive, no more can come out to shoot you. This is perfect if you want to recruit just a certain soldier type on a constant alert map. Also if there is a wandering soldier in the Evasion (orange) or Caution (yellow) phase that spots your subdued enemy, they will be brought back to their feet and the Caution phase will be brought up or reset. Finally, if you have a large number of soldiers held up like this, make sure you do not fire your gun on empty. They may just get angry with you.

Find Johnny from Metal Gear Solid, Metal Gear Solid 2, and Metal Gear Solid 3 as a random prisoner in Infinity Mission.

Have a fair amount of Life Med so you do not lose your soldier. It also helps if you found body armor. First, find out where one of your reserve comrades is hiding. Run over to their box to lure the soldiers over. While a soldier with an "A" or better in CQC can slam enemies down to the ground and knock them out, this other method is recommended as it does not require high CQC skill, just technique:

Punch a nearby enemy and run behind them while they flinch.
Quickly press Square again to get them in the hostage hold.
Rapidly press Square to choke and fully knock them out (five star K.O.)

Note: They do not need to be directly in front of the box for it to work. There is some leeway in range, but for the last one you may gave to haul them to the box in the hostage hold, then knock them out. Finally, you must use the Codec because after subduing all enemies you are frozen and the mission is complete. To get all of them, make sure the final knocked out enemy's shoulders hit the ground before you press Select.