The speaker is sitting in a waiting room of some kind, though the poem never says where, and uses the idle time to turn the situation around. Being made to wait, they suggest, might show them what it feels like when they make other people wait. That idea is quietly humbling: the speaker admits to causing the same small frustration they now feel.
The second half moves into stranger territory. Someone who is late or unreachable is "present in absence," and the poem compares this to a body being carried to its burial by several people. The image is odd and a little unsettling. It makes the missing person feel both weighty and gone, and it makes waiting feel like a kind of vigil. The "little bed" could be a coffin, or a stretcher, or something gentler; the poem leaves it open.
The mood is hushed, reflective, and slightly uneasy, as if ordinary patience had turned into a meditation on absence and death.