The trivia item below may give away important plot points.
Yosi is dead. "That beaker in his hand contains pure mercury". Miss Fischer casually picks it up. First, 100 ml of pure mercury would weigh about 3 pounds, a startling thing to encounter. Second, elemental mercury is not particularly toxic because the body can't absorb it well. Methyl mercury and other organomercuric compounds, howeve, rare severely toxic.