While the scene at 0:23 is probably the most iconic CQC scene in the series, I kind of prefer the one at 21:11. Naked Snake had to resort to use a gun, even if it was just a tranquiliser. And the two guys he knocks out at 0:50 really put up no fight. The lightly touch each other and that's enough for them to go unconscious. The next guy is similar. Compared to that, the one in MGS4 is more smooth, I think, and doesn't contain enemies that just give up.