Observer is a type of Person. Person wants (to) Escape. 
Lead is a synonym of Front. Front is related to Lobby. Lobby can be used for Sit. Sit is related to Demonstration. 
Observer --IsA--> Person --Desires--> Escape 
Lead <--Synonym--> Front <--RelatedTo--> Lobby --UsedFor--> Sit <--RelatedTo--> Demonstration 