If you study the National Geographic Explorer rendition of the Silk Air 185 incident,you'll notice that Captain Tsu Way Ming tried SEVERAL times to offer Fisrt Officer Duncan Ward some water before he left the cockpit,right before the plane's dive. Considering what Ming is accused of,it is my suspicion that Ming was insistent on offering Ward some water so that he could,either,poison him,or disable him,so that he could immediately put the plane into a full-speed dive without meeting any resistance. So,apparently,since Ward kept refusing his offer of some water,Ming left the cockpit right before the dive,knowing that he would have to attack Ward in some manner to keep him from being able to interfere in his evil plan to get revenge against Silk Air. And,yes,he deliberately chose the date of the Silk Air crash because it coincided with the date of the fighter jet crash that his military comrades perished in,but he himself escaped because he was having problems with his jet,and he left formation and returned safely. Survivor's gulit.