you are likely to find Needle in/at/on Hospital. you are likely to find Illness in/at/on Hospital. Illness is related to Heal. Heal is related to Fix. 
Uncover is derived from Cover. Cover is the opposite of Expose. 
Needle --AtLocation--> Hospital <--AtLocation-- Illness <--RelatedTo--> Heal <--RelatedTo--> Fix 
Uncover --DerivedFrom--> Cover <--Antonym--> Expose 