Yahoo News ran an AP article where this quote was obtained: "Wisconsin pharmacist Steven Brandenburg, “He’d formed this belief they were unsafe,” Ozaukee County District Attorney Adam Gerol said during a virtual hearing."
What I find more alarming, is the possibility of Brandenburg's regular customers receiving prescription medications which Brandenburg may have changed or modified before he was arrested for making doses of Covid-19 vaccine unusable?
It is plausible that Brandenburg may have determined some medications were not the best choice for his customers and changed or modified what medications they were prescribed.
I wouldn't normally think this was plausible, except hospital staff over the years have been convicted of murdering patients in hospitals. This is not too extreme to ponder whether, "Angels of Death" may be at work other places than hospitals.