The point being discussed is Finnish Expert Harri Ruotsalainen's recently state view int he press that a fire on the car deck should be ruled out as part of the investigation is based on a theory that one of the cargo containing highly inflammable/toxic materials was letting off fumes, so a member of the crew may have had the bright idea of trying to push the vehicle into the sea via the car ramp. The evidence for this are some burnt looking panels ont he car rmap, the 'Mr Skylight 1 and 2' messages that were definitely played over the tannoy, the sheer amount of pumps in operation as witnessed and the confirmation of at least two crew members of seeing a load of water splashing the cctv monitors in the car deck. In addition, the stern ramp had been opened slight at the top suggesting someone was letting fumes escape.
Of course, as with most fire alarms, there may not have been any fire at all but someone had triggered a fire warning and seems to have set of the fire pumps. In addition, the 'water flooding into the car deck' may well just have been the drencher system in operation.