i used to have a short talk with any new-to-town coworkers or students at my unis -- there were many of them
i'd stress that if they were ever anywhere in the city & had the sense that something was wrong, or someone was suspicious, they should GTFO immediately. even if that meant breaking into a run or looking foolish or possibly racist. to just get out of a situation if you had any inclination of danger.
Baltimore has problems. but it prepared me so well to deal w the unexpected