Multiple if statements on a single control do not work correctly

I am building out a 2-level navigation sidebar. I have a button that does this:

IF A and B {

Do X

}

IF A and C {

Do Y

}

The button stops working entirely unless I remove one of the statements. Using the ELSE statement is entirely useless as it breaks the next IF statement. What is the point of prototyping using conditional statements if when using more than one it breaks?