You can accomplish this by using a combination of MATCH, CHOOSEROWS, and INDEX functions.
Start by finding the row that contains the zone of interest with MATCH(D11,C4:C5,0). This searches column c and produces the relative row number that contains the desired zone, in this case 1.
Now find the column in that row that contains the specified value with MATCH(D12,CHOOSEROWS(D4:L5,MATCH(D11...)),0). This searches the row described above (1) and produces the relative column number that contains that value, in this case 5
Now find the number of pallets in the top row with INDEX(D3:L3,1,MATCH(D12...)). This selects the cell in the top row from the column identified above (5).
Putting it all together produces the formula =INDEX(D3:L3,1,MATCH(D12,CHOOSEROWS(D4:L5,MATCH(D11,C4:C5,0)),0))
If you prefer, you can break the formulas up. For example, if you put the formula =MATCH($D$11,C4:C5,0) in cell H11, then H11 contains the row of interest and the second match formula can be simplified to =MATCH($D$12,CHOOSEROWS(D4:L5,H11),0). If you put this formula in H12, then H12 contains the column of interest and the final formula gets simplified to =INDEX(D3:L3,1,H12).