Sudden is related to Flash. Flash is related to Explosion. Explosion can cause/lead to Destruction. 
Output is related to Current. Current is related to New. New is related to Return. Return is related to Back. 
Sudden <--RelatedTo--> Flash <--RelatedTo--> Explosion --Causes--> Destruction 
Output <--RelatedTo--> Current <--RelatedTo--> New <--RelatedTo--> Return <--RelatedTo--> Back 