Don't scroll too fast or it won't be able to keep up. Results can be retrieved from local storage.

ExportGoogleDomainContacts.user.js

// ==UserScript==
// @name     Export Google Domain Directory Contacts
// @version  1.0
// @description Export Google Contacts Domain Directory to LocalStorage
// @match    *://contacts.google.com/*
// @require  https://ajax.googleapis.com/ajax/libs/jquery/2.1.0/jquery.min.js
// @require  https://gist.github.com/raw/2625891/waitForKeyElements.js
// @grant    GM_addStyle
// @run-at document-start
// ==/UserScript==
//- The @grant directive is needed to restore the proper sandbox.

waitForKeyElements (".PDfZbf", printNodeText2name);
waitForKeyElements (".hUL4le", printNodeTextEmail);


function printNodeTextEmail (jNode) {
    var bacon = jNode.text().trim();
    appendToStorage('emails', bacon);
    console.log("PROCESSED!");
}

function printNodeText2name (jNode) {
    //console.log ("NAME: ", jNode.text().trim() );
    var eggs = jNode.text().trim();
    appendToStorage('names', eggs);
}

function appendToStorage(name, data){
    var old = localStorage.getItem(name);
    if(old === null) old = "";
    localStorage.setItem(name, old + ", " + data);
}

//for(var i =0; i < localStorage.length; i++){
//  console.log(localStorage.getItem(localStorage.key(i)));
//}
//sleep(50);
//window.scrollBy(0, 80);
//setTimeout(function(){".yDmH0d".scrollBy(0, 100);},500);