personally, i consider this the superior version.
It tells a competent story, but I don't think it was exceptionally well-written, and I was left wanting just a sentence or two more that would make me really care for the two characters and their apparent struggle to connect with one another one last time. You spend an awful lot of time describing the fights in a very 'he does this. then he does this' type of fashion that gets awkward and stale.
For example.
Dr. Jacobs stood up and replaced his empty magazine. The containment breach siren began to sound. The entire facility rocked as he stood up. He ran down the hall and turned left at the end of it. A huge fire blocked his way in this direction, so he grabbed a fire extinguisher off the wall and went to work. The fire wasn't quite out before he heard the screeching of metal.
It isn't terrible, but I don't think it's very interesting to read. I would have put-
The sound of breach sirens ringing in his ears, Dr. Jacobs locked a fresh magazine into place. The facility seemed to rock as he got to his feet. He took a sharp left at the end of the hall, and was greeted by a blistering turf of flame. Tearing a fire extinguisher from the wall, he went to work, lashing chemical foam towards the glowering twists of amber and yellow, stopping only when he heard the screech of metal pierce his brain.
Now, I'm by no means the next J.R.R. Tolkien, but when you have such a short word count I feel as if you have the breathing room to play about with words far more than you would in a more exhaustive tale. The language doesn't merit the situation you've placed the characters in. If they're just walking to the shops, you can just say 'they walked to the shops.' When they're fighting 'green-haired monsters' and 'living fires', I would personally expect a bit more.
I do still like this tale in an odd way. It's simple and sweet and a little heartwarming, but my gut tells me it just doesn't hold up against some of the other works I've seen. -1 for now.
