Well it doesn't really matter does it? The king moves out of check because if it doesn't he would be theoretically captured on the next move. In the situation above if the white king takes the queen the knight would theoretically be able to capture the white king. It does not matter if the black king comes under attack as once the white king is captured the game is over.
Check by pinned piece, is this a legal move?
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If black queen moves to d4, is it legal for the king to capture it? The knight on c6 is theoretically protecting the d4 square, but it is pinned to the king by white's queen and does not protect the square in reality, until the pin is broken.