Of course, the employees want the company to continue, and weren't told much at this point so it is understandable that they didn't like the statement.
> We are concerned about late-stage AGI development becoming a competitive race without time for adequate safety precautions. Therefore, if a value-aligned, safety-conscious project comes close to building AGI before we do, we commit to stop competing with and start assisting this project
That wasn't the case. So it may be not so far fetched to call her actions borderline as it is also very easy to hide personal motives behind altruistic ones.
The statement "it would be consistent with the company mission to destroy the company" is correct. The word "would be" rather than "is" implies some condition, it doesn't have to apply to the current circumstances.
A hypothesis is that Sam was attempting to gain full control of the board by getting the majority, and therefore the current board would be unable to hold him accountable to follow the mission in the future. Therefore, the board may have considered it necessary to stop him in order to fulfill the mission. There's no hard evidence of that revealed yet though.
So instead of having to compromise to some extent but still have a say what happens next you burn the company at best delaying the whole thing by 6-12 months until someone else does it? Well at least your hands are clean, but that's about it...