Calm is a different concept from Trouble. Trouble is the opposite of Okay. 
you are likely to find Discussion in/at/on Meeting. Meeting is related to People. you are likely to find People in/at/on Conference. Conference is related to Press. 
Calm <--DistinctFrom--> Trouble <--Antonym--> Okay 
Discussion --AtLocation--> Meeting <--RelatedTo--> People --AtLocation--> Conference <--RelatedTo--> Press 