Create an array from table (Power Query)

Hi guys!

I'm attempting to create an array that has one single input to one single output coming from a table. I currently have a table with multiple columns and I want to map two columns together.

A sample table is supplied below:

let
    Source = Table.FromRows(Json.Document(Binary.Decompress(Binary.FromText("LYu3DcAwDMB+0ezBXfaYXl4w/P8bYQANBMiBY0gQJwsE72W6IRFfIVonfINknfEdsnXBDyjWFT+hWit+gVo3/IZm3fEHunXwxPsPqjLnBw==", BinaryEncoding.Base64), Compression.Deflate)), let _t = ((type nullable text) meta [Serialized.Text = true]) in type table [Column1 = _t, Column2 = _t, Column3 = _t])
in
    Source

The sample input looks like this:

Considering I may have 1000+ records, I want to be able to create an array with the expected output where I select and map Column2 to Column3.

EDIT: Considering all items from Column2 and Column3 will be unique

let
    Source = Table.FromRows(Json.Document(Binary.Decompress(Binary.FromText("LYu3DcAwDMB+0ezBXfaYXl4w/P8bYQANBMiBY0gQJwsE72W6IRFfIVonfINknfEdsnXBDyjWFT+hWit+gVo3/IZm3fEHunXwxPsPqjLnBw==", BinaryEncoding.Base64), Compression.Deflate)), let _t = ((type nullable text) meta [Serialized.Text = true]) in type table [Column1 = _t, Column2 = _t, Column3 = _t]),
    ExpectedResult = 
    [
        A = 100,
        B = 200,
        C = 300,
        D = 400,
        E = 500,
        F = 600,
        G = 700,
        H = 800,
        I = 900,
        J = 777
    ]
in
    ExpectedResult

How would this be possible? I think I've done it before but I'm currently having a brain fart.