Post War Dreams

After speaking with Antonio for Engineering (and then Hudson again), make your way back down to the ledge you jumped off earlier (where the ladder leading down to Antonio is). Instead of taking the ladder down, head right (kill any Militia members in your way). You'll come to another ladder leading up. Climb up one level and head right. Speak with Everett and exhaust the conversation. The trophy will unlock shortly after the conversation has ended.