How to display error on specific template?

I know in wp-config.php editing this line:

define('WP_DEBUG', true); - on display error
define('WP_DEBUG', false); - off display error

I just want only display error in specific template or page.

@PieterGoosen gave some good advice. Focus on that,

But if you really wan it, then you can set debug ON temporarily on your website this way.
In your wp-config.php use this instead.

if ( isset( $_GET['debug'] ) && 'debug' == $_GET['debug'] ) {
  define( 'WP_DEBUG', true );
}

Then access your website homepage/any page and add ?debug=debug at the end of URL.
For example if you have page www.example.com/about/ then use this link to enable debug.

http://www.example.com/about/?debug=debug