Building an Eloquent Query based on data in model instance

I am building a system where administrators can create "questions" as part of an automatic quiz. It is really more of an audit so that administrators can create items to see if data in the table exists or is a certain value for all data.

here is an example of a question model instance:

 #original: array:9 [▼
     "id" => 1
     "name" => "User has an email"
     "question_condition" => "NOT"
     "question_condition_val" => "null"
     "method" => "contact"
     "property" => "email"
     "created_at" => null
     "updated_at" => null
]

What I want to do is get this instance, and then use the data to construct an eloquent query. The example above would give me this eloquent query:

$user->contact()->email

Then, I can use conditionals based on the question_condition and question_val fields like so:

if($question->condition == "NOT") {
    if( /*$user->contact->email */ != $question->condition_val) {
	    //the user has satisfied the condition set by the question
        return 1;
    }
    else {
        return 0;
    }
}

What I have been trying to do is use PHP's Variable functions to access the method listed in the $question instance, but that doesn't seem to work.

So is there a way to use a variable to access a method on an eloquent model? The model always stays the same, but the method changes based on the $question.