Why do you say quads are less safe than twins. Fire fighting/suppression in the holds is the same on all modern aircraft. Quads tend to have much more redundancy built in in all areas not just the engines. The Twins have had to have these items added and the MEL usually is a higher level because the twins usually have less redundancy.
Having operated ETOP's twins in the past and now a long haul quad, I know what the companies and I prefer - a quad.
Have a nice day
