A reached statement is declared unreachable despite `break 2;`

Phan 4.0.6
php-ast version 1.0.11
PHP version used to run Phan: 7.4.16

Running the following code:

<?php declare(strict_types=1);

$text = 'Some "text"';
$output = '';
$textLen = strlen($text);
$startPos = 0;
$spacePos = strpos( $text, ' ', $startPos );
$quotePos = strpos( $text, '"', $startPos );
$pos = ( $spacePos === false && $quotePos === false )
  ? false
  : min(
    $spacePos === false ? $textLen : $spacePos
    , $quotePos === false ? $textLen : $quotePos
  );
while (true)
{
  if ($pos === false)
  {
    trigger_error('bad',E_USER_ERROR);
  }
  switch ($text[$pos])
  {
    case ' ':
      if ( $pos == $textLen -1 )
      {
        trigger_error('bad',E_USER_ERROR);
      }
      $output .= substr( $text, $startPos, $pos-$startPos) . $text[$pos];
      $startPos = $pos + 2;
      break;
    case '"':
      $output .= substr( $text, 0, $pos );
      break 2;
    default:
      trigger_error('unexpected',E_USER_ERROR);
  }

  $spacePos = strpos( $text, ' ', $startPos );
  $quotePos = strpos( $text, '"', $startPos );
  $pos = ( $spacePos === false && $quotePos === false )
    ? false
    : min(
      $spacePos === false ? $textLen : $spacePos
      , $quotePos === false ? $textLen : $quotePos
    );
}
echo $output . PHP_EOL;

will output Some Some "text via the statement on last line (47). On running this through phan, it reports:

phan-test.php:47 PhanPluginUnreachableCode Unreachable statement detected

This is incorrect. phan seems to be failing to properly account for the break 2, which exits the while loop and makes the last line reachable.

Start by running Phan 4.0.6 or the latest release on the PHP reproduction in this issue and confirm the unreachable-code report on the final echo statement. Trace the control-flow handling for the switch's break 2, which should exit the surrounding while loop. Done means Phan no longer reports that reached statement as unreachable while preserving valid unreachable-code diagnostics.