The poem is short and a little puzzling, but its pictures are simple. In the first stanza, the speaker looks at a hand and treats it as the start of a door. That odd idea suggests that reaching out, opening, and touching are how we begin to travel anywhere. The door becomes "most of my road," a way of moving "in and then out," so life feels like a repeated crossing between inside and outside, which the title echoes.
The second stanza turns to a memory, or perhaps an imagined past life: "the first time I was a dog." The speaker remembers only play, with "nothing yet at stake." The tone is wistful and light. Being a dog stands for a time before worry, when nothing could be lost.
Together the stanzas set up a contrast. The first is thoughtful and grown-up, aware of paths and thresholds. The second is carefree and innocent. The mood is quiet, curious, and gently nostalgic, with a hint that stakes arrive later.