Php foreach give 2 users random value

You could do something like:

$oldcw = NULL;

foreach($users as $user) {
    if($oldcw){
        $newcw = $oldcw;
        $oldcw = NULL;
    }else{
        $newcw = mt_rand(1, 52);
        $oldcw = $newcw;
    }
    ....
}