All credits go to
PowerPyxAn extremely easy way to do this achievement:
Special Operations can be started from the quest board at your 3 main camps (Madrugada, Valle De Oro, El Este). It’s only available online, but can be played solo.
For this the 2nd Spec Ops map “Maceo” is recommended. First you must beat it once to unlock Mastery Level 1. You can check difficulty from the mission start screen (bottom right corner).
At Mastery Level 1 hostages will start spawning across the map (they also spawn at Mastery Level 2 & 3, but for trophy purposes it’s faster and easier to play Mastery Level 1). These are tied-up people and will be indicated by a red glowing flare in the air. Their locations change each try, just look in the sky for the red glowing flare. When you go near them it will show a popup on the left side of the screen saying “Lola’s Informants Operation Nearby”. Kill the enemies around them and untie the hostages. Then restart the Operation immediately and repeat. No need to finish the mission, it still counts when you restart immediately (press Options > System > Restart Special Operation). They can quickly be farmed this way. You don’t need 30 in one mission, this isn’t possible anyway. It only spawns 3 per run. All 3 will always spawn together in the same spot. Save as many as possible, restart, repeat.
YouTube: