It gets so, so much worse once you leave.
All of a sudden you're not on top of it anymore - your acquired defences are stripped away almost immediately. You don't automatically know that something's appened from the sad songs on Galgalatz; you find out on the Ten O'Clock News like the rest of the world, and by the time you've scrambled to call your parents and see they're OK they're in bed and over it already. To you it's a major drama, which is weird because it's never been that before. To them it's just another weeknight.
In time you forget how quickly events move there. You write an email to a friend the morning after hearing something on the news and get a bewildered response - that was a whole two days ago for them, after all. Gradually you get left behind. You fall out of the loop. You don't live at the same level of intensity anymore and they can't slow down enough to include you.
Making the customary round of calls after each attack to see that your friends are all safe is now a major financial investment that you can't make - so you get left behind with the fear, thinking oh well, I'd hear about it by now if someone had been hurt, and the guilt, the terrible gnawing guilt that you are here safe and sound and they are getting killed, blown up, shattered, riven, torn, mutilated...
You can leave it behind but it doesn't make life any easier. In some ways those of us who are dealing with it on the spot have it easier.