Here is one way.
val(:,:,1) = [
0 0 0 0 0
0 0 0 0 0
0 0 0 0 0
0 22 0 0 1
0 0 0 0 0
33 0 -1 0 0
0 0 0 -1 0
0 0 0 0 0
0 0 0 0 0
0 0 0 0 0];
val(:,:,2) = [
0 0 0 0 0
14 0 0 0 0
0 0 4 0 0
0 0 0 0 1
0 0 0 0 0
0 0 0 0 0
0 0 0 0 0
0 16 0 0 0
0 0 0 2 0
0 0 0 0 0];
newval = zeros(size(val));
newval(6,:,:) = reshape(val(val~=0),size(val(1,:,:)));
I made up some 3D data based on your first "slice". Then, I create a newval matrix that is the same size (but all zeros), and fill in the 6th row with the non-zero values from val.
