If you insist...

AC2: =INDEX('Page 2'!$C$5:$S$5,MATCH(A2,'Page 2'!$B$2:$R$2,0))


But I must urge you to reconsider the merged cells.
They really cause more problems than they solve.

If it is just for visual effect, A very similar effect can be achived with "center accross selection"
Found in Format Cells - Alignment - Horizontal - "Center accross selection"