Moments of Awkwardness

So, what would it feel like to be the guy hanging out with Elvis Presley when he had his infamous bathroom incident. Imagine that were you and Elvis were instead one of your friends. How long do you think it took for that guy to realize... Oh hey this guy has been in the can for some time... maybe I should check on him. Long story short, how long should you leave someone alone in the bathroom before you can presume they pooped themselves to death and call for help?