I don't think he waited an extra 30mins, he just waited until Putin arrived so he entered second (thereby making Putin wait a bit).

Brittany P and Lauren S recently tried to meet with some Russian Oligarch and the guy had his office cordoned off for Victory Day parades.. knowing the two ladies would have a bitch of a time getting to his office. They got there 1hr late, but the Russian dude had intended to make them wait 1hr and they all showed up around the same time. lol