you are likely to find Lock in/at/on Entrance. Lock is a type of Overwhelm. Overwhelming is derived from Overwhelm. 
Viewer is derived from View. View is a synonym of Inspection. Inspection is a synonym of Examination. Examination is related to Doctor. 
Entrance <--AtLocation-- Lock --IsA--> Overwhelm <--DerivedFrom-- Overwhelming 
Viewer --DerivedFrom--> View <--Synonym--> Inspection <--Synonym--> Examination <--RelatedTo--> Doctor 