Controller cant handle 3 zombies (LAG SPIKES)

I joined the beta to help search for bugs, but also to enjoy whats new. I played on one of my survival worlds, and took an adventure, until i encountered 3 zombies(one was a zombie villager), the game started to lag so much that, my controller wasnt working the way it should have been. I ended up getting killed, and when i respawned, it wasnt so laggy like it was with the mobs. Please help fix these lag spikes, thay can really break the game.