Query category help, custom post type

Hi, I have a custom post type, and the following query is working. I’m using Shortcode Exec PHP to use it in my page.

$args = array( 'post_type' => 'testimonial', 

'posts_per_page' => 1, 'orderby' => 'rand' );

$loop = new WP_Query( $args );
while ( $loop->have_posts() ) : $loop->the_post();

    echo '<div class="test-text">';
    the_excerpt(); echo '</div>';
endwhile;

However, I need it to appear in two places, side by side. That’s working, too, but I need to ensure that the same result never appears in the two places. Is it possible to do a result +1 type of query for the second one? Or, I have set up categories of left and right (slug), but I don’t seem to be able to query a specific category for each side.

Any suggestions as to what I might be missing? THanks.