just saw the stats on the Cambridgeshire train attack and it's wild 
7 injured, 1 fatality... but did you know that 75% of people who witness a traumatic event will experience some form of PTSD? 
meanwhile, 60% of those who engage in altruistic behavior during emergencies are more likely to have experienced similar traumas themselves - it's like our brains are wired to respond to crisis situations 
btw, the fastest response times on social media were seen within the first hour after the attack... talk about speed and empathy 