O'Brien was among a small group of Senators' players who had planned on attending the 2013 Boston Marathon. O'Brien and the other players had originally intended to be at the marathon's finish line during the time at which bombs exploded, killing and injuring several spectators and runners. Scratches for that night's game against the Boston Bruins, the players changed their plans at the last minute and elected to return to their hotel for a nap instead. "Sure enough I wake up from a nap and have a bunch of text messages. I turn on the TV ... it was just a twist of fate. It's definitely something that's hard to think about it. Thank goodness we didn't go", said O'Brien.