In this context "wound up" could be replaced with "ended up." When something "winds up" (the present tense version of "wound up") happening, it means it was unintentional or an accident. Someone will usually be surprised when something "winds up" happening (just as the narrator in your blerb is surprised). I hope this helps.

Similar to what Vanessa said, 'wound up' in this paragraph is a phrase used to explain the result of something. "I put the coffee on the table and it wound up staining the surface!" "I got stuck in traffic this morning and wound up being late!" In other words "I got stuck in traffic this morning, and this resulted in me being late!" Hope the examples help you understand the usage of this phrase. This phrase can have another meaning however when used in a different context. If you say "I am really wound up!" it means "I am really angry" or "annoyed." This is because the literal defintion of being wound up means to be tangled. Like if you literally 'wind up a clock' or 'wind up a ball of string.' It might be a bit confusing that they can have such different meanings, but it's a good tip to remember. You will most likely hear both of these examples in casual conversation.