What is Robin's reaction to Preston's description of the Ebola and Marburg viruses? What does this show about his personality?

A professional hunter and safari guide, MacDonald is unconcerned about the threat of the Marburg virus inside Kitum Cave. He laughingly assures Preston that, if necessary, he will roll Preston up in a tent and drop him off at the entrance to Nairobi Hospital. However, more seriously, MacDonald notes that he has a gallon of bleach in his Land Rover. This shows MacDonald to be brash and rather ignorant of what this virus can really do.