Yes, of the surrounding environment. This is a single building more or less single-purpose-build to be contaminated as a last measure.

All these exercises are inherently economical -- they could just have walked away on the first day and have the whole thing melt down, and the surrounding area wouldn't have been any better or worse off, radiation-wise.

As I understand it, spreading out the waste leads to more material being contaminated. Surrounding concrete, pipes, cranes beams etc... Most equipment used ends up contaminated. I know an engineer who cleans these places up, and its mad, bad and very very expensive. Massive amounts of planning for simple jobs. Plotting safe routs, zones, dose rates etc. Maximum containment makes the job way way easier.