To my mind, thinking of oneself as being in an iron pot doesn’t communicate safety, but it did to Jerusalem’s leadership, who were accused by God of planning evil and giving wicked counsel:
Ezekiel 11:3They say to the people, ‘Is it not a good time to build houses? This city is like an iron pot. We are safe inside it like meat in a pot’
So God told them what sort of iron pot they were:
Ezekiel 11:7 This city is an iron pot all right, but the pieces of meat are the victims of your injustice.
And that it wouldn’t protection them:
Ezekiel 11:8-9 As for you, I will soon drag you from this pot. I will bring on you the sword of war you so greatly fear, says the Sovereign Lord. I will drive you out of Jerusalem and hand you over to foreigners, who will carry out my judgments against you.
Because God had said again and again through His prophets: the lack of justice in Israel and now in Jerusalem had left Him nothing to protect.