It doesn't make sense so maybe they are trying to tell us something. It's puzzled me from the start that there was an almost immediate assumption that Corrie had left in a vehicle, this only makes sense if there is information that hasn't been made public yet as it is, as you say, nonsense to say that you can be sure he didn't leave on foot yet appear to have no sight of a vehicle other than the bin lorry which you categorically state he wasn't on or in
they seem to have been giving pointers without saying this is what happened