Listening to the Sports radio in KC and even they are saying the Chiefs will be a step slower tomorrow.
I can imagine that it would be hard for the Chiefs to "rally behind this" the next day - if only because my interpretation of "rally" has a certain context.
Similarly, I can also imagine how it may also be difficult for the Panthers to stay focused themselves; while their team didn't lose a player in this event, there is an overall NFL brotherhood that they are all a part of.
Seriously, does anyone really believe that the coaches for either side are going to be making "let's use this as motivation to [win it for him | knock them while they're down]" speeches in their respective locker rooms? No - I can see both sides being a bit more melancholy at gametime, assuming the game goes on as planned rather than being slightly postponed to allow for proper investigations to continue (stadium is now a crime scene, after all)