If you look at the video closely, you will see that many women had their purses with them, and at least two men took their bag or briefcase. So the guy with briefcase was not the only one who could not bear to part with his stuff. After he finally got his butt off the slide, a firefighter runs over and at least another person came down the slide. The firefighter then signaled some more, but there did not appear to be anybody else.

I am not defending the guy with the briefcase, but I do know a little something about human behavior when the person is placed in a stressful situation and especially one with which he is unfamiliar, and probably never experienced before. It is not everyday that passengers evacuate from a plane through the slide. It is very difficult to tell how different people react to different stressors.

This man appeared to be one of the last people out of that plane. Assuming that he was second to the last, it is possible that he thought he could take his briefcase and not cause any delay to anyone else. And he must have seen that others were taking stuff with them. Note also that the last guy to come out waitied until the firefighter got there and signalled him before he, too, jumped out. Of course, he would not have known that his briefcase would break open when it hit the ground.