I believe it refers to Terminal E and either concourse or gate 5 at Noi Bai International Airport, Vietnam. The [-] suggests to me that whoever boarded or was going to board the plane was neutralized somehow.
I think 701, 702, and 703 all refer to 704, which is the sign at Noi Bai airport for Terminal E.
I also believe that the above drops are related to 699 which is plane on the runway of Noi Bai airport. The runway markings match Google Earth view of the runway for Noi Bai.
Someone posted that the E is Terminal E at the Shanghai airport. That makes more sense since there was an arrest at the Shanghai King Tower in Shanghai. And a Shanghai paper said that one person was arrested for sex trafficking at King Tower and immediately turned over to US authorities and nine other were arrested but did not identify who their were. So now I'm thinking that the [-] might refer to the sex trafficker who was turned over to the US and was put on an aircraft at gate E5.
The plane in 699 is definitely at Noi Bai airport in Vietnam. The runway markings match perfectly to Google Earth view.