Having it in the engineering section certainly would have made it easier for Finny to hide without being seen. That may have been more difficult if it was located at the bottom of the sensor dome on the saucer section. In any case I will second the thought that it never really bothered me they didn't go into more detail in the show about where it was or what it did. Actually the fact that they didn't tell you really made me think a lot about it. Part of the fun I guess.