Rav Zilbershtein said, and I would guess he was talking about any laws the government might pass regarding the CoronaVirus including a possible lockdown but I'm not sure, that everyone has to obey the law - except for one person. The one person that does not need to obey the law is the chochom, the wise man, of the city - he can do whatever he wants and break any law he decides to. The chochom of the city is Rav Chaim Kanievsky - he is not subject to any law - only to the laws of Hashem. If Rav Chaim decides one thing, nobody can tell him anything else.

Interesting. 

What's the source for this exemption? Is it the chochom of the country and there is only one or the chochom of each city and Rav Zilbershtein was simply talking about Bnei Braq? 

Aren't we all subject to the laws only of God, but those laws also include following the laws of the society we live in (ie dina dmalchusa dina)?