you sure it's the page file? page file or hibernation (safe sleep) file? Memory swaps to /var/vm/pagefile0 etc....

unless you disabled it deliberately through a 3rd party tool or command line, your macbook will dump all of RAM to disk as soon as it sleeps - this is your "safe sleep" recovery if power drops too low. It doesn't wait around for low power to dump it out, it does it as soon as you close the lid.