I'm not sure employment law in Canada, but if you were in the US I would say that this would be a completely fair thing to do. After a quick google search it do

I'm not sure employment law in Canada, but if you were in the US I would say that this would be a completely fair thing to do. After a quick google search it does look like it is a little bit more difficult for employers to terminate employees and so this may have put them in a tight spot. It seems to me like you have some leverage that you have with this company and top management does not like this. I would be prepared for them to try to take away this leverage by hiring to fill this skills gap, cross training, etc. At the end of the day I think you did the right thing. You could have left them in the lurch by giving them two weeks notice and walking, and even then no one will hold that against you. At the end of the day I think any reasonable party will realize you are being fair with them, as long as you continue to deliver high quality work and remain transparent with them.