Now if you can stomach it, check out this video from about an hour before #4 starts blowing smoke or steam. That beam or whatever it is, on the right area near the lower part of the stack, came out of the ground. The anti-nuke people are going ape-crap over this. I have no idea what came out of the ground over there earlier tonight. And it appears that the smoke/steam is coming from possibly multiple sources since it was rolling into the camera view from the far right.
2012-02-06 17:08 light rays connects to spot light @ tepco fukushima
That video is a little over 1 hour before #4 started blowing smoke/steam. And around the time that TEPCO decided to inject boric acid into #2. Also reports that other SFP are getting too warm #3 and #5.
In that short video above, note that at the end there is a bright flash. That is similar to the bright flash that was documented in the video archives back in early January when an unreported and rumored explosion occurred in #4. So it looks like #4 went boom again. Small explosion with a bright flash. You can see the sequence in the Tepco video linked below.
First there is an arclight (for lack of a better descriptive term) that appears at 14 sec (17:04:54 JST). It is located to the right of the far right stack between the far right crane. A small one. Then the big arclight comes out of the ground at 26 sec (17:09:02 JST). It is below and left of the bright light TEPCO uses to cover up the exotic radioactive gas bleed building. Then at 30 sec a bright lightning flash occurs that lights up the sky. That is probably when #4 went boom. Smoke or steam starts slowly filling the air at around 1:28 (17:29:43 JST).
2012.02.06 17:00-18:00 / ふくいちライブカメラ (Live Fukushima Nuclear Plant Cam)
Actually that now could be considered to be the best case scenario. The worse case would be that the exotic gas bleed building, which is connected underground to all the reactors, is getting overloaded with what is coming up out of those melted reactor core masses.
Just my 2 cents.