That picture looks more like the emergency exit hatch on a king air than a main door to a Boeing.
Never been in a 777, could that be an overwing exit door?
On ELT's Since it's been 6 or 7 pages, and that's about how often it comes up. An ELT is designed to work in a potentially
survivable crash, not to transmit if you hit the water at 600 MPH. Not to say the ELT isn't going off, but it would be separated from it's antenna. There is a picture of one of the AF flights recorders at the bottom of the ocean on the internet. If you look you will see it is still in its rack and the rack is separated from its mounting location.