Hard to imagine real astronauts taking such stupid risks

*Spoiler alert!*

Let me just say, I really enjoyed the movie, but I thought the slow killing-off of all of the characters was its weakest point and it ultimately keeps me from loving the film instead of just liking it.

In the scene just before James dies, he and Andrei are trying to repair the busted communications panel on the outside of the ship. They have less than 30 min of oxygen left and realize that part of the panel is frozen so they use their last few minutes to try to pry it open. James looks nervous and says, "Are you sure you don't want to put heat on it first?" Wouldn't that be protocol? Why would they try to force it like that? Why wouldn't they just go back to the ship, now that they've assessed the situation, and come back and fix the panel later? It's not like it was urgent. I just can't imagine an astronaut prying something off of the ship, much less staying out on a space walk until they only have a critical amount of oxygen left. (Also, as far as I know, most of the stuff on the outside of the ship that astronauts might come into contact with are made to have smoother edges and to be soft as possible, so as not to rip their space suits.)

Later on, Katya stays out on her surface walk on Europa until she also has very little oxygen left. Not only does she not return to the ship long before she enters the danger zone, but she walks further away from it... toward a mysterious light that they have already associated with unstable conditions and higher levels of radiation.

Then when they're taking off from Europa, William gets out of his seat and starts fiddling around with the equipment without closing the partition between the cockpit and the rest of the command module first.

It seems to me that all of their deaths could have been easily prevented, and they were just killed as a means to give the movie the atmosphere of a horror flick in which the characters die one by one. To me, it undermined everything that was good about the film. I'm not saying they all should have lived to the end, but their deaths could have been more organic and therefore more meaningful.