How to get the name and value of ContstantExpression in x => x.property

I'm creating a simple way to get the Name and Value of Expressions in C#. However, I found a case I cannot figure out. See the code below:

public void GetValue_Object_TIn_Property_Test()
{
    string val = "value";
    var tuple = Tuple.Create(new object(), val);
    Expression<Func<object, string>> expression = x => tuple.Item2;

    Assert.AreEqual(val, expression.GetValue());
}

The .GetValue() method is my extension method.

Basically this expression-tree consists of a LambdaExpression, two MemberExpressions and a ConstantExpression, in that order.

When I try to get the name of tuple.Item2 I get memberExpression.Member.Name from the last MemberExpression. This gives me "tuple" instead of "Item2". How can I get "Item2" instead?

Also, when I try to get the value of the expression, I get the entire tuple instead of Item2. I'm using the following method to get the value:

public override bool TryGetValue(
    MemberExpression memberExpression,
    out T value
) {
    value = default(T);
    bool success = false;

    var fieldInfo = memberExpression.Member as FieldInfo;
    if (success = (fieldInfo != null))
    {
        var valueObj = fieldInfo.GetValue(expression.Value);
        if (success = (valueObj is T || valueObj == null))
        {
            value = (T)valueObj;
        }
    }

    return success;
}

Where the MemberExpression again is the last MemberExpression. What am I doing wrong here? What is the exact case I am missing?

Thank you in advance