Taking a column is easy with the map function.
// a two-dimensional array
var two_d = [[1,2,3],[4,5,6],[7,8,9]];
// take the third column
var col3 = two_d.map(function(value,index) { return value[2]; });
Why bother with the slice at all? Just filter the matrix to find the rows of interest.
var interesting = two_d.filter(function(value,index) {return value[1]==5;});
// interesting is now [[4,5,6]]
Sadly, filter and map are not natively available on IE9 and lower. The MDN documentation provides implementations for browsers without native support.