Ann: Final Director's Interest Notice - Lev Mizikovsky, page-27

Even after resignation selling shares you own or have a related interest in 'on inside information' could well see someone behind bars. Likely the current down market reacting to a couple of resignations and not taking chances.
However 2 recent resignations suggests there is some 'inside' discontent which is why we have seen the reaction.
In the past we have seen many key resignations in companies followed later by bad news. So many are not taking the risk - and why should they.
Maybe its part of the cleaning up process aimed at getting some new blood in? - that's the optimistic outlook.
Only hindsight will show the answer.