Amazon warehouses are Tilt-Up Construction. Basically 4-to-6-inch thick cast concrete panels on a grid on metal tubes as joists. Support pillars with basic trusses, and a roof tying it together.
You lose a ton of stability once that roof is gone. You lose a truss or a few pillars, and I'd imagine it came down like a house of concrete cards very, very quickly after the first wall section fell.
It has no chance against a tornado direct hit. You need a dedicated shelter structure for that.
The 2 rooms themselves were basically a 12” enclosure (including the ceilings). There were also concrete pillars in the room to reinforce the structure. During normal times we used them for various activities. But, at least during a couple of summers, we had to evacuate (from the cabins or wherever) there. The program staff (people in charge of the camp) were always monitoring the meteorological radar 24/7. This was in North Texas, which is tornado alley. The camp was an hour north of the Dallas/Ft. Worth metroplex.