Crisis communications is PR playing defense. I've worked crises ranging from workplace shootings to scandalous lawsuits and more, and the stakes are never higher when it comes to a brand preserving buyer trust.
This article on managing media crises from MarketingProfs.com offers some good advice on how marketing and public relations teams should work together in crisis management situations.
Some other resources on crisis communications:
The 10 Steps of Crisis Communications
Crisis Communications Planning Template
13 Rules of PR Crisis Management
Enjoy.