Elementary is a different concept from Middle. Middle is related to Inside. 
Heal is related to Illness. Infection is a type of Illness. Infection can cause/lead to Death. Death is related to Bell. 
Elementary <--DistinctFrom--> Middle <--RelatedTo--> Inside 
Heal <--RelatedTo--> Illness <--IsA-- Infection --Causes--> Death <--RelatedTo--> Bell 