Dave Bonta's short poem is compressed and a little cryptic, so it helps to read it as a series of small, connected feelings. It opens with a warning: too much "dull freight," meaning heavy, tedious burdens, might make people "think like horses," plodding along with their heads down. The speaker then pulls away from that image and says they "play to play," which suggests doing something for its own sake, without a purpose or a payoff.
The mood turns uneasy in the last lines. The speaker realizes how close they came to "having broken," and the title, "Close call," backs that up. The comparison to "the loss of words / to a shut pen" is open to interpretation, but it seems to say that breaking would feel like a writer losing the ability to write. The poem feels relieved but shaken, as if the speaker has just stepped back from an edge and is still catching their breath.