diff --git a/lib/IndexController.php b/lib/IndexController.php
index 12d63bf..2962a6d 100644
--- a/lib/IndexController.php
+++ b/lib/IndexController.php
@@ -84,17 +84,20 @@ class IndexController extends Controller {
 			return $response->withHeader('Location', '/register');
 		}
 
+		// Get the numbers from the session, and then reset them
 		$numbers = array_map((function($i) { return intval($i); }), explode(',', $session->session_data['numbers']));
-		$query_values = (array) $request->getParsedBody();
+		unset($session->session_data['numbers']);
+
+		$form_values = (array) $request->getParsedBody();
 
 		// Check CSRF
 		$csrf_token = null;
-        if (array_key_exists('_csrf', $query_values)) $csrf_token = trim($query_values['_csrf']);
-        $this->container->get('csrf')->check('csrf', $csrf_token);
+		if (array_key_exists('_csrf', $form_values)) $csrf_token = trim($form_values['_csrf']);
+		$this->container->get('csrf')->check('csrf', $csrf_token);
 
 		// Check the math question
 		$given_sum = null;
-		if (array_key_exists('verify', $query_values)) $given_sum = intval(trim($query_values['verify']));
+		if (array_key_exists('verify', $form_values)) $given_sum = intval(trim($form_values['verify']));
 		if ($given_sum != $numbers[0] + $numbers[1]) {
 			return $this->requestGET($request, $response, array_merge($args, [
 				'message' => 'The provided verification was incorrect.',
@@ -103,9 +106,9 @@ class IndexController extends Controller {
 
 		// We're good, send the notifications
 		HookMachine::execute([self::class, 'sendAlert'], [
-			$query_values['username'],
-			$query_values['tilde'],
-			$query_values['message'] ?? '[no message provided]',
+			$form_values['username'],
+			$form_values['tilde'],
+			$form_values['message'] ?? '[no message provided]',
 		]);
 
 		// And return a success message