Mark and Cora Lijek, a young couple serving in their first foreign service post, knew the slogans — “God is great! Death to America!” — and had learned to ignore the din as they went about their duties. But today, the protest sounded louder than usual. And when some of the local employees came in and said there was “a problem at the gate,” they knew this morning would be different. Militant students were soon scaling the walls of the embassy complex. Someone forced open the front gate, and the trickle of invaders became a flood. The mob quickly fanned across the 27-acre compound, waving posters of the Ayatollah Khomeini. They took the ambassador’s residence, then set upon the chancery, the citadel of the embassy where most of the staff was stationed.