Was it ethical to...

Science is learning about new things and to revive the decapitated head was ok to learn what had happened to the engineers ..

This seems like a ridiculous thing to do while examining this well preserved specimen of the Engineer’s head by hooking it up to electrical current but there is a reason behind this. It is to serve the theme of the story. First, it illustrates humans trying to “play god”. The electricity reminds us of Frankenstein, being reanimated by electricity also (though his head doesn’t explode). In fact, the subtitle of Mary Shelly’s Frankenstein book is “The Modern Prometheus”. That is no coincidence. So the characters do something very unscientific and out of character in order to build further on the overall theme discussed above.

They weren't reviving it. They were stimulating the nervous system trying to get a better handle on it's physiology. Unfortunately, they applied to much stimulation, waking muscle memory and reanimating the growth of the black goo.

... Take it back to the company labs...duh...

@patch I laughed so [i]very[/i] hard at that. Thank you.

They were trying to let the growth finish what it started...The BURST was exactly what an ALIEN needs to come out of its host. If the body was attached, I am guessing the chest would have burst

As Zed said, they weren't trying to bring a severed head back to life, which is, of course, not possible.

I loved how it began to stink up the lab. I wish they would have let us see it more with the skull blown open and brain exposed.

@loseyourname -"As Zed said, they weren't trying to bring a severed head back to life, which is, of course, not possible." Of course the head could not sustain life without a body, but it did appear to regain consciousness (reanimate) through that brain stimulator or whatever the name is, or at least it appeared to do so. That "revival" contraption is supposed to stimulate the brain cells back to function even after they were considered dead from what I understand form the "brochure" in the Weyland site. Not sure what is meant with the black goo, guess I'm gonna have to watch it again...