Why does Codeigniter crash on the line with call_user_func_array?

Question

CodeIgniter

Given:
cms on Codeigniter
php 5.3.10
The system is down.
Falls on line:
call_user_func_array(array(&$CI, $method), array_slice($URI->rsegments, 2));
500 error.
But! If you do
var_dump($CI);
call_user_func_array(array(&$CI, $method), array_slice($URI->rsegments, 2));
It doesn't drop anything. :(
What's the point?

Answer 1

What's in the $method variable?