I'm not sure if I picked it up from a documentary or book, but worth noting that the photographer Frank Hurley dived into the ice water and chopped through a wood wall to rescue the glass plate negatives from the sinking ship. I'm not sure what the best source for this is, but it's at least mentioned in [0]
[0] https://www.pbs.org/wgbh/nova/shackletonexped/images.html