Yes, people should be cautious around emergency vehicles, but there comes a point when emergency personnel should be cautious of their surroundings and even utilize an iota of common sense when exiting their vehicle and even place their vehicles in a staggered manner to protect themselves when they are outside. It's a sad event, but police officers do not have the luxury of complacency and this should be reiterated by their departments and possibly even included in the training classes to a greater degree.
Just my thoughts on the matter.