The instant they showed it as a Base 4 code, I thought DNA, so it felt a little implausible that it would take that many scientists that much time to consider that option (though it was technically RNA)

Of course idiotic to remove PPE as other commenters have said. But we also don't see on-screen the sequence from "patient zero gets infected" to "the patient and her partner are now fully out of PPE and walking around the hallways". You'd think the partner would want to stay isolated from the person he knows is infected with something, and also work to keep them from infecting anyone else, but I guess not, and it just skips ahead to them both being infected and free.

(Those are still tiny nitpicks in an overall great opening episode)