Help Random Shutoff?!!?

Hello all,

Just a small concern/question; after playing the game: Injustice Gods Among Us for about an hour or so, I exited the app and closed it and everything was working just fine. After about five minutes after closing the app the tablet froze and then I held the power button for about 10 seconds and it shut off, I plugged it into the charger to see if the battery had just died but it was at a charge level of 59%. Just wondering if you guys had any thoughts as to why this happened or some tips on how to prevent it. I'm going to uninstall Injustice after I beat it, it uses too much battery and memory. Thanks for your help!