From what I understand, someone helped the woman and then the laughter began. I assume the girl was uninjured by the experience.
Laughter can ease up a tense situation. Cracking jokes helps generating that laughter. I feel it's a better response to a patronizing "You should be careful next time" or a depressing comment about what could've happen.
Maybe it has to do with me being a guy or my culture (I'm portuguese) but me and my firends are constantly cracking jokes about each other, mostly when something bad happens. (Not BIG BAD, of course. I wouldn't make a joke about a death of a relative) I remember helping a fallen friend up with one hand and with the other in my mouth trying to contain my laughter.
Please don't assume that laughting at someone or cracking jokes has the purpose of hurting them. You should learn to laugh with people, at people and, most importantly, at yourself.