Despite our seeming obsession with risk in this country, we really do a terrible job of thinking about it in useful terms. For example, our government regularly subsidizes risky behavior by providing flood insurance to communities and people who build in the 100-year flood plain. Similarly, many techniques of urban design and planning or of some of our 'fads' like New Urbanism or the construction of weird buildings at odd angles with stupid facades, actually make us less safe. I am not saying that there has to be a trade-off, just that there often is.
Examples of this problem include narrow streets (makes response and evacuation more difficult) and close-together housing (makes fires more likely to spread), both tools of New Urbanism. Another example are the weird buildings built in Seattle, Vancouver, and Portland by crazy architects (these buildings are often less stable and are prone to tip over, etc). I am not saying that working in concert is not possible, just that it does not happen. There are ways for us as hazard mitigation planners and regular urban planners to talk to one another and make a conscious choice over where on the continuum between a perfectly stable building with no windows on a huge street and with no quality of life or a beautiful street with fascinating buildings prone to collapse and chandeliers that impale you while you sleep, we want to be. Since these are extremes, the answer is somewhere in the middle.