PHP--an Array in an Array? Not sure, using ajilion MySQLidb Class need to get value of raw Query

PHP--an Array in an Array? Not sure, using ajilion MySQLidb Class need to
get value of raw Query

(PHP newb here--can read code somewhat well, working on writing)
I think I have an array in an array. using this for MySQL calls:
https://github.com/ajillion/PHP-MySQLi-Database-Class
my call:
$params = array($mta_name);
$mta_uid = $db->rawQuery("SELECT mta_uid FROM mtas WHERE mta_name = ?",
$params);
echo print_r($mta_uid);
ends up with this:
Array ( [0] => Array ( [uid] => 1 ) ) 1
I just want the '1' . Have tried mta_name['0'] and ['1'] and ['0']['1'] /
['1']['0'] / ['1']['2'] etc.
Whenever I have issues always find you guys and usually solves. First time
posting.
Many thanks!