The "15" on the map looks more like "IS", but the "15" on the rubbing from the notepad that the map came from looks like "15."
This episode borrows heavily from the story of a bride who wore a gown that was worn by a corpse, thereby causing her death from the skin absorption of formaldehyde. Although it is a compelling story, this entire sequence is nothing more than an unsubstantiated urban myth, with the actual probability of it happening at virtually non-existent.