I was telling my grandson this morning that I found a flaw in the story and that was that the scientist and a part were needed to detonate the bomb. What's up with the other 4? My grandson and I watched Sunday and Monday together... we are HUGE fans and what fun we have sharing the show. Oh and for all the pc folks, he is old enough to watch.
And even if, as you asked about there being 4 or 5 total of those parts, they would have gone up in the blast. Unless of course there are 4 more parts scattered all over the country? They don't usually leave such gaping inconsistencies that I notice and I'm sure they won't here either. I'm just curious how they will work it out.
IMHO, I got the impression that the nuke that went off, was a more "modern" version. This would imply that the others may be older technology. Their detonation mechanisms may be completely different. However, the next question is why the terrorists wanted this one to go off first?