And it was practically cruel to force Dortmund on to the field this week, so soon after shrapnel from one of the bombs was found in a headrest on the team bus and mere hours after the players were told they were lucky to be alive.
Such an unsettled psychological state was at times reflected in their performance, as midfielder Nuri Sahin, clearly still shaken by the previous night's events, explained on camera after his side's defeat.
"Until I was on the pitch in the second half, I didn't think about football," Sahin said. "I know football is very important. We suffer with football. We love football. I know we earn a lot of money, we have a privileged life, but we are human beings. There's so much more than football in this world."
And yet while that final sentiment especially could not be more true, while football can feel distinctly unimportant in times of turmoil, the opposite can also be accurate. Sometimes - far from frivolous - sport can almost be essential.
Events on the field can be a chance to display a collectively stiff upper lip. They can also allow those impacted - athletes included but especially fans - to move past a frightening event and forward with their lives.
That was clear in 2015, when French and English football fans joined together to sing La Marseillaise at Wembley four days after the Paris attacks, four days after several explosions rocked the area surrounding Stade de France while, inside the stadium, the national team were playing Germany.
And it will be clear again, the next time extremists mount an attack in continental Europe that casts an immediate pall over sport.
Dortmund probably shouldn't have been made to focus on football this week; indeed, there's no doubting what will be running through the players' minds when their team bus sets off for the stadium ahead of this weekend's Bundesliga clash with Eintracht Frankfurt.
But, equally, one of the powers of sport is to move trauma to the background, if for only 90 minutes at a time. It's an uneasy alliance, switching from a moment of life and death to a meaningless game, but one that has become all too necessary.