How is a perpetual check reached in this puzzle? This puzzle on chesstempo caught my eye. We play as White:
[FEN &quot;4Q/4p1bk/1p1qp2p/p1p1n2B/4P/2P3B1/PP4P/6K b - - 0 1&quot;]

1. Nf3

Side Note: The answer is of no importance here, so no spoilers from me. :)
The puzzle is tagged with avoiding-perpetual, yet I cannot see the perpetual check here. It has been discussed in the comments under the puzzle:


Why not just gxf3 and after Qxg3+, run away with the king to the left board edge and hide between pawns?
Because he can’t hide. When the king reaches c2, the black queen attacks from e2. When the king is on b3, the queen moves to b5, and perpetual.


However, I do not think this is quite right. b5 is protected by the White queen.  So, where and how is perpetual reached on this board? I would appreciate a hint instead of the full solution. :)
I think that Kf2 is actually the winning move for White and the perpetual results after gxf3.
[FEN &quot;4Q/4p1bk/1p1qp2p/p1p1n2B/4P/2P3B1/PP4P/6K b - - 0 1&quot;]

1. Nf3 gxf3 2. Qxg3+

Now the White king can not escape the perpetual even though the Black king is very close to checkmate.