I think the board was surprised when nobody bought their claim of Sam’s vague wrongdoing.
Actually, I think every plot twist we’ve seen has been a surprise for them as they have consistently acted without 5 minutes of foresight.
And not just with the drama. For example, according to Stratechery, the clause in the contract saying Microsoft couldn’t use GPT-4 as a foundation for their own models was recently removed in a contract revision. If you don’t like your CEO, and Microsoft likes your CEO, and Microsoft has the rights to your models and code, it doesn’t take much to add up 2 + 2 + 2 = 6.
In this case, with these stakes, I think it's in the board's purview to understand the implications of firing your CEO with no immediate replacement plan, and the current state of possibly the most important contract your company has would be relevant.