We cannot undo what happened last Monday. We can, however, cease the mad violence for which we are responsible, over which we have control. That would be the truest and best memorial we can offer to those so hurt by last Monday's blasts.
It's hard to run if your leg is gushing blood all over the place and hurting you. Also, the blood makes the ground slippery, and other runners will get mad at you, no matter how hard you try to explain that really, it's that jerk dog's fault.