So I was attempting to hack the terminal in Camp Mccaran on the airstrip (the one next to the door requiring a key) and I got down to one attempt left a couple of times so I exited the terminal to start again. After the third attempt I completed the hack, learned about who was coming and going, and was on my marry way back to go kills some raiders. Well, to my surprise, after about 5 steps away from the terminal I get a message that Boone has died. Now what is interesting about this is that 1) we were in Camp McCaran with no enemies and I have sided with the NCR and 2) when I turned around to find him, he had vanished. So my companion died without any enemy attack and then vanished somewhere into the wasteland...I tried this again to see if it would occur more than once, which luckily it did not. I wanted to see though if other people had any issues with companions dropping dead for what seems to be no particular reason at all. I wouldn't have cared so much if it were Veronica...at least then I wouldn't have to hear her talk.

I got the same problem but with Ed-E, whenever enter or exiting buildings and fast traveling, it just dies no reason at all.

Solution: Do Not use companions. ( it svcks, but at least you don't have to worry about babysitting them or getting in the way when fighting, this happens to me a lot to the point of being more trouble than help, and then to top that they just dissapear (DIE) with whatever items they had stored)

I am okay if they died in battle, or because I forgot about them after using the Wait command, but come on DEAD on a transition screen.