2Dimensional Array question

[halex]

$i = 0;
$matrix = array();
while ($rec = mysql_fetch_array ($result)) {
	$one = array();
	$one[0] = $i;
	$one[1] = $rec['COLUMN1'];
	$one[2] = $rec['COLUMN2'];
	$one[3] = $rec['COLUMN3'];
	$one[4] = $rec['COLUMN4'];
	$matrix[$i] = $one;
	$i++;
}

Questions:
1: $matrix is now 2D array?
2: to get value of $rec['COLUMN2'] of 3rd element I can do like
this?

$mySearchedValue = $matrix[2][2];