It's not clear if she even died from plague. The Russian-language version of the article lists various "versions" of what happened, and her breaking a test tube is only listed as one of the versions. Sounds like random rumors but at the same time, you can't trust the government either (which says no one has tested for plague positively). What's clear is that an employee at an "anti-plague' institute suddenly died from pneumonia-like symptoms, which certainly sounds suspicious but interpreting it as evidence of a plague infection may also be an overreaction