It means that what happens to the Seneca will happen to one of us, so the Seneca are playing it safe by letting the wounded man aboard. It's like they're saving him, one way or another. They don't seem to have much humanity. If the Seneca dies, one of us will suffer the same fate, but I don't think that will happen. The commander and the doctor on board know very well what they're doing; they're people we can trust. You'll see that the Seneca is saved, but I don't think we'll see the chief say thanks.
Hey, and here I was hoping you'd marry the chief, hahaha, what a cruel joke, I'm sorry.