Hard to Kill/Mortally Wounded - what exactly happens?

[BraselC5048]

Definitely no assistants, sickbay has maybe 13 guys having to deal with 70+ casualties over 5 hours, and likely another 20 in a 20 ish minute period. For an hour-long surgery, there just isn't enough doctors to spare a second one. That said, another doctor or two at the same time is working on his (numerous) other wounds using First Aid or Surgery, likely both, First Aid stop the bleeding, the Surgery to fix the damage, although that could be done once he's stabilized.

Does Trauma count as a specialization, anyway? It could well matter.