Is it permissible for me to benefit from an abandoned room and its contents after the doorman has given me permission to take the room?

For abandoned items, there are two situations: If their owners are known, it is not permissible to take them or benefit from them except with their permission, unless it is known that they left them for whoever wishes to take them. If their owners are unknown, these items fall under the ruling of "Luqata" (found property). If the item has no value and its owner does not care for it, there is no harm in taking it and benefiting from it. However, if it has value and its owner cares for it, it is not permissible to benefit from it until it has been publicly announced.