Modern medical technology, and even the technology of late 1990s do not require a dead body to understand how it worked. At least on the crude level of X-COM autopsy reports. MRT, X-ray, some probing, some syringes... Unpleasant, not good for health, but unlikely to be fatal, even to frail Ethereals.
There can be some research item, possibly a special lab, that would allow to get autopsy reports from studying living specimens. It can be a purely Earth invention, like lasers, or something derived from alien medical technology (Abductor ship, "alien surgery", cloning...).
Has anybody tried that?
Does the engine allow to make some X-COM base facilities go deeper? If yes, then alien alloys, for example, could unlock 4-floor base modules with double volume.
Deeper living quarters, labs and workshops would house twice as many people. Deep stores would have double capacity. Deeper radars can have 3 times as much electronics crammed under the same dishes, which would mean 3 times more power and something like 70% higher detection chance. Hangars and rocket launchers would not benefit from this, since they need the area, which doesn't change. Don't know about shields.
Has anybody tried this?