Big Brother

I was getting ready to vacuum the office a little while ago when Peyton panicked because Ashtyn was on the floor in the treacherous path of the vacuum. "No bacuum, Ashtyn's not safe!" he cried at me several times as I readied the beastly Kirby. For curiosities sake, I turned on the vacuum to see what he would do, fully expecting him to run for safety. To my surprise and delight, my son plopped on the floor next to his baby sister and threw his arms in front of her for protection. As proud a moment as it was, I was also perplexed at my 3 year old son's mind...why on earth does he fear I would suck up his little sister with the vacuum?