Save Everyone Calling for Help in Chapter 3
This is the second missable Trophy/Achievement in Chapter 3 and it’s another easy one to miss as you have to go against what the game’s main objective is asking of you.
Proceed through the Chapter as normal and when you return to the Director’s Office after being promoted to SOLDIER First Class and unlocked Materia Fusion, you’ll start the Assault on the Shinra Building section as Genesis clones attack the headquarters. Director Lazard will instruct you to head for the entrance, but this is counter to what you actually want to do.
As you take the elevator down, it’ll get stuck and you’ll be presented with two options. Choose “Get off and look around.” to have Zack get off on the SOLDIER floor and run into the first person who needs saving. You’ll be immediately thrust into a battle against three Red Saucers that are weak to Thunder (!Thunder Blade is very useful here if you have it).
Once you save him, look nearby for another SOLDIER on the ground, head over to him and examine him to be ambushed by another group of Red Saucers. Once they’re defeated, he’ll hand over an Ether and be on his way.
There’s one more group of people to save before making your way to the entrance and you can find them by heading to the Training Room. Once inside, you’ll trigger a battle with another with six Red Saucers so make use of Thundara or !Thunder Blade to hit more than one at a time and don’t let them surround you. After the battle, you’ll be given a choice, choose “I won’t tell anyone.” and you’ll get a whopping 5,000 Gil for your silence.
That’s all for the Shinra Building so finally head to the entrance, deal with the enemies at the lobby and you’ll eventually find yourself in Sector 8.
Once you have control following the scenes, there are two more people to rescue before you take off after Cisnei. To the right of your starting location are some people cornered by a Sweeper, once again Thundara and !Thunder Blade are your friends here and you’ll get an Amulet as thanks.
The final person can be found at the opposite side, also being cornered by a Sweeper. Deal with this enemy and you’ll get some Earrings. If this is the final person you needed to save, you’ll have the Everyone's Hero Trophy/Achievement pop at this point.