Extracting data from User field, within a repeater (ACF)

user_field.php

<section class="member-list">

	<?php if( have_rows('repeater_field') ): ?>

		<?php while ( have_rows('repeater_field') ) : the_row(); ?>

			<?php $user = get_sub_field('user_field'); ?>
			<?php $userID = array_values($user)[0]; ?>

			<?php $first_name = get_user_meta($userID, 'first_name', true);  ?>
			<?php $last_name = get_user_meta($userID, 'last_name', true);  ?>

			<div class="member">

				<h2><?php echo $first_name . ' ' . $last_name; ?></h2>

			</div> 

		<?php endwhile; ?>

	<?php endif; ?>
        
</section>