The Omega was carrying a carefully contained and absolutely deadly alien parasite. The carrying and deadly parts are still true. Mission control is very clear that you should at all costs avoid contact with the parasite.
They're just not very clear on how.
Whether in the classic Who Goes There or John Carpenter's big screen version The Thing, what's certain is that with an alien parasite in the mix pain and paranoia won't be far behind. Infection is certain, survival is not.
New "Permanent" cards mean that infected crew can lose control and threaten the mission. At first, careful movement control and partial quarantine will serve to control the outbreak. But it will spread, and eventually more extreme measures may become necessary.
Permanent cards can change the rules of survival in the middle of a game, changing how the parasite evolves and effects crew, making infection a constant and unknowable threat.
As all good fans of alien infections know, if it lives in the blood, testing the blood is how you destroy it. Using the medical pod to lower crew morale and make the tests is a high risk move, especially since it forces potentially infected crew to congregate and spread the disease. But better that than risk its spreading turning into it hatching. Until you manage to remove the parasite, remember,
You Are Home.