[FireVolkhov]

Механизм прост, после сбора всех директив с ноды, angular сортирует их через функцию

/**
     * Looks for directives on the given node and adds them to the directive collection which is
     * sorted.
     *
     * @param node Node to search.
     * @param directives An array to which the directives are added to. This array is sorted before
     *        the function returns.
     * @param attrs The shared attrs object which is used to populate the normalized attributes.
     * @param {number=} maxPriority Max directive priority.
     */
    function collectDirectives(node, directives, attrs, maxPriority, ignoreDirective) {
...
      directives.sort(byPriority);
      return directives;
    }

/**
 * Sorting function for bound directives.
 */
    function byPriority(a, b) {
      var diff = b.priority - a.priority;
      if (diff !== 0) return diff;
      if (a.name !== b.name) return (a.name < b.name) ? -1 : 1;
      return a.index - b.index;
    }

A флаг terminal заставляет оборвать цикл применения директив, тем самым выкидывает все директивы с меньшим приоритетом

/**
     * Once the directives have been collected, their compile functions are executed. This method
     * is responsible for inlining directive templates as well as terminating the application
     * of the directives if the terminal directive has been reached.
     *
     * @param {Array} directives Array of collected directives to execute their compile function.
     *        this needs to be pre-sorted by priority order.
     * @param {Node} compileNode The raw DOM node to apply the compile functions to
     * @param {Object} templateAttrs The shared attribute function
     * @param {function(angular.Scope[, cloneAttachFn]} transcludeFn A linking function, where the
     *                                                  scope argument is auto-generated to the new
     *                                                  child of the transcluded parent scope.
     * @param {JQLite} jqCollection If we are working on the root of the compile tree then this
     *                              argument has the root jqLite array so that we can replace nodes
     *                              on it.
     * @param {Object=} originalReplaceDirective An optional directive that will be ignored when
     *                                           compiling the transclusion.
     * @param {Array.<Function>} preLinkFns
     * @param {Array.<Function>} postLinkFns
     * @param {Object} previousCompileContext Context used for previous compilation of the current
     *                                        node
     * @returns linkFn
     */
function applyDirectivesToNode(directives, compileNode, templateAttrs, transcludeFn, jqCollection, originalReplaceDirective, preLinkFns, postLinkFns, previousCompileContext) {
...
      var terminalPriority = -Number.MAX_VALUE,
...
      // executes all directives on the current element
      for(var i = 0, ii = directives.length; i < ii; i++) {
...
        if (terminalPriority > directive.priority) {
          break; // prevent further processing of directives
        }
...
        if (directive.terminal) {
          nodeLinkFn.terminal = true;
          terminalPriority = Math.max(terminalPriority, directive.priority);
        }
      }
...
}