Your only source is Twitter??

How much do you know about tornados? Apparently not a lot. Unlike other potential weather disasters, you literally only have minutes to seek shelter when a tornado hits. And while weather bureaus can usually give you an indication of where it's headed, again, you're going to get a few minutes warning.

What did you want Amazon to do? Allow people to leave the building where they could become airborne? Be hit by projectile at hundreds of miles per hour?

The safest place to be in a tornado is a well-built structure. With X number of employees on site and only 6 died is amazing.

But you'd have to have some knowledge of weather disasters to know that and not really on Twitter for your information.