TP2 randomly powers off

[Meanee]

So, I am getting fairly frustrated with my phone randomly powering off. Starting to miss important calls/texts and it's driving me nuts.

I am using MightyROM from Feb 5th, no auto locking apps or anything similar.

I know that it's definitely powering off, since I know people usually want to confirm it's off, not in sleep/suspended/etc. As soon as I push the power button to "wake up from sleep", phone vibrates and give me a startup screen.

It's also worth mentioning that it's happening in low signal areas, such as subway, or my office, where signal is not too stable.

Any ideas/hints/suggestions?