Pardon, but how on earth do you go about to find an explanation for uncorroborated dog alerts? As they are uncorroborated, nobody can explain what the dog alerted to, we simply don't know & most likely, we never will. What we're left with is speculation, which is OK, as long as one is aware that's all it is.
Oh yes, pure speculation, based though on the fact Eddie is an EVRD (that provides speculating with a certain justification). Mr Grime, in the film, even says that Eddie's alert in the parents' bedroom doesn't necessarily indicate a corpse was there, a draught could have sent there the volatiles molecules, trapped in the corner.
When someone disappears leaving no trace, no sign, no clue, one is entitled to wonder why the EVRD alerted in this flat and not in the others. Wonder, nothing else.
One is always entitled to wonder about things in this world, I fully agree 
One thing I personally wonder about is the following; you have two dogs, both who are said to be trained to alert to the scent of minuscule traces of human blood. Then you have a large holiday resort where thousands upon thousands of people pass through every year & have done so for a number of years and the ONLY apartment both these dogs alerted to was Apt 5A. That, if anything, needs some explaining....... >@@(*&)
I'm sure an expert will be along shortly to put me right, but this is my understanding of it Mrs B
If Keela, the blood dog had been trailed through the resort independently, then yes, she would have been alerting frequently
She was not though. She was, in effect, a 'check' to Eddie, the cadavour dog
Where Eddie had already alerted, there was a possibility that he was alerting not to the 'scent of death' but merely to blood
Consequently, Keela was brought in and used to establish whether or not it
was blood that Eddie had alerted to
Where Keela 'jointly' alerted it was suggestive of blood being present
Where Keela did not alert to an area in which Eddie
had alerted, it was suggestive that he had, indeed, detected the scent of death ( there being no blood present )
