Sentence:  As I dug in behind one of the bales we were <WSD>using</WSD> as protection , I grudgingly found myself agreeing with Oso 's logic , especially when I imagined what would have happened to Missy if Old Knife 's large party of screeching warriors had overrun our company . 
Meaning of the word marked with <WSD> tags:  put into service; make work or employ for a particular purpose or for its inherent or natural purpose