Shaw
Prison.
Riley
Albuquerque. See I can do it too. Snorkel.
Shaw
That's where the map is. Like he said, "Fifty-five in iron pen." "Iron pen" is a prison.
Ben Gates
Or it could be, since the primary writing medium of the time was iron gall ink, the "pen" is... just a pen. But then why not say a pen, why say iron pen.
Shaw
Because it's a prison.

