If you would like to boost and use 2 controllers, start a versus match on The Concert Finale of the Dark Carnival (chapter 5) with you as the human and the 2nd controller as the infected.
Kill off 1 of the unneeded survivors leaving only 2. On those towers in the bleachers there should be a defibrillator on each one (2 total) and MOST OF THE TIME, not always, 4 speed shots where you turn the music on in that little booth on the stage. Just blast your team till they have little life and finish them off with that infected controller. Let one die before they go get heath on their own and leave one on the ground bleeding. You can keep reviving the same survivor with the speed boost all 4 times but you can only use one defib per survivor.
So when your done with all the speed boosts let that 2nd survivor die and defib both of them. Sounds like a lot of work but as soon as you do it the first time the second time and third are a breeze, it's the easiest way I've found so far. If you have problems with the survivors healing, just injure yourself in the beginning real bad and use them all right away yourself. It should only take 3 games total for the speed boosts, and 5 for the defibs.
If you have a question about this guide please ask, or if I left something out that's important let me know.