It is entirely possible that he was tasked with traveling to procure a relic, and used the opportunity to make sketches along the way. Not only did he record architectural details and draw machines, he also drew subjects "from life."
Some of them are figures of saints or Christ, likely taken from art, but some are obviously activities of real people. The first illustration here is a soldier at rest. We get some idea of what a soldier would wear; we see what looks like chainmail under his tunic, along with a chainmail coif. Unlike the simplified straight lines of his machine drawings, here we see attention to the detail of folds and pleats in the fabric.
Another interesting sketch from life is the wrestlers.
This page has been turned sideways so that he can include the wrestlers, but as much as he cared to represent them carefully—the folds of their loincloths, the contours of their bodies—it was just an idle addition.
His caption reads: Here begins the method of representation as taught by the art of geometry, to facilitate work.
On a page of the twelve apostles (and three other figures, he writes: Here you will find the images of the the Twelve Apostles, sitting. Villard de Honnecourt greets you and begs all who use the devices found in this book to pray for his soul and remember him. For in this book will be found sound advice on the virtues of masonry and the uses of carpentry. You will find strong help in drawing figures according to the lessons taught by the art of geometry.