He reacted to the booth of the Scenic not the boot. Booth does not equal Boot.
I have personally never heard of a "booth" of a car.
boothnoun [ C ] uk /buːð/ us /buːθ/
a small space like a box that a person can go into:
a phone booth
a polling booth
a partly closed area or small tent at a fair, exhibition, or similar event
a place in a restaurant that is beside a wall and where there are two long seats, often with high backs, with a table between them
http://dictionary.cambridge.org/dictionary/english/boothThe original Portuguese documents refer to the "mala da viatura" or to the "zona da bagageira" as captions to the rear area of a car in which one would normally place luggage.
http://www.mccannpjfiles.co.uk/PJ/59-DA-27.htmBesides which, Eddie only reacted to the outside of the driver's door, and subsequently to the key card placed in that door's storage area. Whatever you wish to call the luggage compartment at the rear - Eddie didn't react to it.