In this case, the police told people they need to be “aware of their surroundings”. No mention of WHAT they are supposed to be aware about, I assume because we can all GUESS at what we are supposed to watch out for, and they certainly cannot SAY what we are supposed to watch out for.
I’m assuming they were also warning of the usual boy-murderers on the loose inside the mall - you know, the kids who kill because they ran out of acne medicine or were thrown off the debate team.