If you should accidentally lose a small object down between the gaps, is it possible to loosen just the section where the object fell or do you need to start in one corner and then remove maybe as much as half the floor to get to the right section?

It is easy to loosen the tiles using the removal tool/hand tool. You can divide the tiles in one row and retrieve the loose item through the gap and then join up the loosened tiles. Takes very little time.