When you're grinding there's significant metal and abrasive dust thrown into the air. Given the airflow they generate and how fine the radioactive powder is even a small nick in the capsule could end up with a lot of material in the air without you noticing it.

A jig to limit grinder motion sounds like really cheap insurance to prevent this failure mode.

I'm curious if the capsules like this are standardized or one-off. The description of the tungsten plug makes it sound like the latter.

In which case a more sane procedure would probably mandate some examination of the capsule, formulation of a plan off-site, then implementation of said plan.

They're only a 20 something million dollar company, so everything is probably done as cheaply and simply as possible.

Like many companies, they may also have trouble hiring people.

If you're using an angle grinder on something you expect some smoke to come out. You might not notice if it's slightly the wrong color.

It depends how heavily it was disturbed. They describe it as like talcum powder. If it's that fine, tiny particles could disperse in the air invisibly.