Don't worry about it too much. I've lived here for fifteen years now and it's a pretty safe area. There can be a few flares every once in a while (like the 2005 riots) but every major city has issues now and then. King's Cross is a place that you want to be a bit careful in, but only during the night - it's just a lot of drunk, rowdy people who can get a bit out of hand with their partying every now and then. Overall, it's not a high crime rate place at all and for the most part there's nothing much to be concerned about as long as you're careful yourself.