Why won't ruby return a variable in a certain if statement

So I'm doing random challenges on codewars.com and the challenge is:

You are given an odd-length array of integers, in which all of them are the same, except for one single number.

Complete the method which accepts such an array, and returns that single different number.

The input array will always be valid! (odd-length >= 3)

 def stray (numbers)

  numbers.each do |num|
    num != numbers[0] ? return num : next 
  end
end

def stray2 (numbers)
  numbers.each do |num|
    if num != numbers[0] 
      return num开发者_JS百科
    else
      next
    end
  end
end

def stray3 (numbers)
  numbers.each do |num|
     return num if num != numbers[0]
  end
end


array = [1,1,1,1,1,2,1,1,1,1,1]
p stray(array)
p stray2(array)
p stray3(array)

when I run the code the stray method always throws a code. other versions work also but what is making that version not work? just want to understand why. Thanks in advance