In a school-shooting scenario, going into whichever classroom is closest after an announcement of a lockdown is standard (this is not a drill). The Fosters' Callie and Brandon, both seniors, duck into a middle school science room being handled by a twentysomething substitute teacher. The sub is frantic, flipping through a binder on school-shooter procedure, not sure how to handle his students or his classroom. The two 17-year-olds know exactly what to do, barricading the doors with a collection of tables and chairs and directing the younger, more panicky kids to stay quiet on the floor. It’s a reminder that these older teens, who would have started kindergarten in a post-Columbine world, are as familiar with school-shooting drills as they are fire drills, and with just a little maturity are able to carry out the plan automatically.

The sub is obviously not great under pressure, showing absolutely no leadership skills or ability to reassure the kids under his care. But he does feel confident that he's prepared for a day at an American school: He's brought his own gun. The pistol ends up nearly getting him killed when he mistakenly pulls it on police, not the potential shooter. But however stupid a decision it is, it has a chilling implication — he feels his life might be put in danger as a teacher. And he isn't wrong.

The Fosters clearly isn’t done talking about gun violence — the potential shooter, who’s motivated to take his father’s gun when he believes his girlfriend, a Foster, has cheated on him, is still out there and is able to sneak into the Foster house. What this season premiere clearly illustrates is the fact that, while the threat of gun violence is always terrifying, to a bunch of teenagers, it's nothing new.