Ellen gives her house number as 4663. But when the team arrives, the number on her mailbox is 17419.
When Michelle is lying in the tub, the striped bathing suit she's wearing is clearly visible under the bubble bath.
As a firehouse captain, Strand should know better than to throw prescription medicines into the trash. They should be safely disposed of at a location that will safely get rid of them. For example, some pharmacies have a collection bin inside the stores.
Mercury is a liquid metal at room temperature and 'runnier' than water (ie. has low viscosity). It would easily run out of the sandwiches when picked up. Most of the workers in the office would be surprised by it's appearance and have commented on it, causing the incidence of consumption to be low.