Lockdown Scenarios News Today : Breaking News, Live Updates & Top Stories | Vimarsana

The time when students and teachers and people who were terrorized by this incident or may have been hurt in this incident, the time at which they knew it was over is a very gray area. as far as we understand it, the perpetrator of the attack, the alleged shooter here, was able to leave the scene in the midst of all this chaos and was apprehended, not on the school grounds, but almost a mile away. that must have created incredible ambiguity. must have really lengthened out the amount of time anybody could have any clarity that this was over. >> reporter: it did and part of the reason we're sti...

Students and teachers are told that in these lockdown scenarios, in these active shooter scenarios, you're supposed to go to a corner of the classroom, a corner of the school, and you're supposed to take cover and you're supposed to stay there until police come to get you or at least until they i have notify you that it'. obviously the shooter had left the school and yet the students and teachers were waiting to be told it was okay to leave. that's one of the things that will come out in the coming days. >> nbc news correspondent tammy leitner, thank you, i know it's been a tough day of report...

Various drills that we do ever since 9/11. >> do you know senator, whether it was one shooter or multiple shooters? >> i don't think we know those details yet. under lockdown scenarios or high-alert scenarios, you make no assumptions. you simply plan for the worst and hope for the best. >> tell us about this navy reserve center on amnicola highway. >> it is mostly training. right up against the tennessee river. there is actually a river park community park right next to it. it is every day when people drive into chattanooga if they come in on amnicola highway. not a popular area. mostly commer...