[gambiting]

But again:

>>highly radioactive material is within reach of any disgruntled office worker.

Like, how would that disgruntled office worker even reach that highly radioactive material? Especially without killing themselves in the process. Hospitals already have extremely radioactive cobalt sources on premises, and they are 1) impossible to get to by a normal employee 2) would kill said employee if they ever did get to them somehow.

[RetroTechie]

There can be a good bit of time between receiving a lethal dose of radiation, and dying (or incapacitated) from that.

Also sources tend to come with shielding. Some portable, some less-portable. Oh and.. use machinery / robots / whatever, with operator outside the danger zone.

Your "impossible" does a lot of heavy lifting here.

[gambiting]

>> impossible to get to by a normal employee

No, it's the normal that does the heavy lifting. A radiation therapy machine does not allow for an easy removal of the source, not without hours of work with specialized machinery. Again, how does a disgruntled office worker do this without immediate attention of security?

>>There can be a good bit of time between receiving a lethal dose of radiation, and dying (or incapacitated) from that

Well, it's really unfortunate, but we have multiple reports from people who have accidentally walked into a room with an open Cesium source at various irradiation facilities - they all reported that they felt incredibly sick in less than a minute. And that's "just" an irradiation source, not an active nuclear reactor. Again, I'm struggling to imagine how a "disgruntled worker" gets anywhere near the actual radiactive material within it.