07: One Bullet

#1. Continue until you encounter the first roof-mounted auto-turret. Circle around the vehicle and avoid the spotlight then enter the next cavern. Make your way to the exit and you'll find a sealed gate. Before heading forth, turn to the right past the vehicle to find a full body armor to the left. Just beside it is the mission's first dog tag.
Body Armor Dog Tag

#2. After the scene with Bella, go upstairs and continue straight to the control switch. Turn right to find another dog tag on top of the console.
Laboratory Lockdown Dog Tag and Laboratory Audio Log

#3. Proceed to the module control room and kill the personnel there. After getting your objective updated, open the door beside Oneal and go downstairs. Once you've reached the lower floor, turn to the right and look inside one of the open boxes there to find the last dog tag of the mission.
Power Cell Dog Tag