Nexus 5 started heating up then died

I don't know anything about these sort of things, never torn a phone apart, but my Nexus 5 just died. Started heating up even when turned off and would not hold any charge. I noticed it was making a gurgling noise when charging and it felt like it was bubbling under the cover, right in the zone where the wifi chip is supposed to be. I had been experiencing trouble connecting to WiFi too before the phone went completely bonkers. I already have a replacement phone coming, but I was wondering if anyone knows what the problem might be. I'm willing to get adventurous with it, it's no use to me the way it is now anyway.