Another worst scene? S09E04 Man On Fire (should have been titled "Men On Fire", but I digress).

The ending of this episode. de Groot (Alan Fudge) and Blair (John Hillerman, later Higgins in the original Magnum, P.I.) knock over shelving units holding plutonium canisters and they roll down an incline toward McGarrett and Danno. The latter two scramble to prevent three canisters from nesting and causing a radioactive disaster per Dr. Ormsbee (Pat Hingle) who is standing near them. I believe this idea is total BS but I don't deal with plutonium on a daily basis so I have no idea. The whole thing is dumb on so many levels: the scenario not only insults the viewer's intelligence, but cheapens the characters. It's plain stupid.