The poem starts with a cold, almost technical description of fire doors, how they hinge and which way they open. Then it moves into a maze of library-like stacks, where "tier on tier" and constant right turns make it easy for a man to go unnoticed. The title suggests that man is the speaker's father, though the poem never says so directly. That distance is part of the point: the father is seen only through structures, metal, and frames.
The feeling is guarded and tense. The speaker avoids saying anything tender or direct and talks about doors instead. The image of a hand opening "in the gesture of closing" captures a mix of reaching out and shutting down. The locked fire door, slammed "to the cores of memory," seems to stand for memory sealed against heat or pain. The mood is cool, enclosed, and a little haunted, as if the speaker is circling something too painful to approach head-on.