Is laughing at absurd but tragic events wrong?

I work for a modest land surveying company in South Florida. Today, a seemingly deranged man parked his van on top of a highway interchange ramp, pulled out a rifle with an American flag stuck in the barrel, put a noose around his own neck, and seated himself on the concrete railing, about 80ft from the other highway below. (The other end of the rope was attached to the van.) On the side of the van, hand-painted letters read "Hippocrates [sic] Traitors." I don't know what he wanted, but his stunt shut down both highways for three hours while police and SWAT tried to talk him down. I happened to be in the area, working on a construction site, close enough to see him sitting on the railing -- and I couldn't stop myself from laughing. While I understand that suicide isn't a laughing matter, the situation was so absurd. I wasn't alone in my reaction. Is that kind of laughter inappropriate or wrong? What explains it, other than the sheer absurdity of the situation? Is it wrong to laugh at absurd but horrible events?