Hour 4 (8.20) The ice shelf braking Antarctica's Doomsday Glacier is about to go, a rare violin gets stolen, and Mark relives the voiceover auditions that didn't go his way. The hour opens on the theft of a very expensive, very old violin, which turns into a detour through the instrument's history and everyone who's held it. Then Tim and Mark on the Doomsday Glacier — Thwaites is nicknamed that because a total collapse would push global sea levels up 26 inches and flood coastal communities. The eastern ice shelf that acts as a natural brake on the glacier is expected to start breaking apart, though scientists put the full collapse on a timescale of centuries, not years. Mark takes it from there with stories from the voiceover audition circuit and what actually happens in those rooms. And the crew closes out going around on their favorite cereals, which gets more heated than it has any right to