Update Apr 5
I finally shopped around for a wire connector (Thanks Jussek for the idea) so I can attach and re-attach the turret from the upper hull whenever I want to. I also bought some supplies for when attaching the connectors. Bought a cheap soldering iron (more on this later), some solder and these -

The sales clerk mentioned flux (the one in the syringe) and a soldering paste. She called it "soldering glue". Both were used for soldering (she says) but couldn't tell me what's the difference between the two and what its used for. Confused, I bought both just to be sure.
Also bought some shrink wraps. I don't know the size of these but just bought the smallest they had. Proved quite useful.
Here's the the wire connector. They didn't have a 3 wire connector in stock so I bought these 5 wire ones instead.
Okay so on with the mod. First I cut off the excess wire from the connectors since I just need 3.
Here it is cut up with the male/female connectors joined together.
Then I cut some shrink wraps to attach to the wires that will be cut. I had to redo a couple of wires that were already soldered and attached since I forgot to add the shrink wraps.

(so don't forget that step)
Since only one of the wires (out of 3) that connects the turret to the upper hull is of a different color (red), I decided to key that wire with the blue wire in the connector.
Then cut one of the turret wires at the place you want the connector at. Don't cut all 3 turret wires at once as things can get confusing since 2 wires are of the same color. (black)
Strip the wires and don't forget to attach the shrink wraps before soldering.
Solder the wires together. Here I used the soldering paste instead of the flux. I got scared I might accidentally prick myself using the mean looking syringe so I didnt use the flux. This pic actually shows the thing I did wrong and I had to recut the wire and redo the solder all over again. As you can see I placed the shrink wrap too close to the solder that the heat shrank it before I can move it to cover the join. So don't do what I did.
Also half way to the soldering (when I successfully soldered 3 of the wires on one end of the connector) my el cheapo soldering iron gave up and wouldn't heat the solder enough to melt it. I had to attach the rest of the wires by just twisting the wire strands together. Hopefully the wires hold by pure mechanical force alone and not using solder as glue. The upside of this was, it was easier to slide the shrink wraps over the join as there were no thick solder goop blocking it.
Move the shrink wraps over the join to cover it. Then I just move the soldering iron close to the wrap to shrink it tight.
Here it is with all the wires finished.
Here's a wide view shot of the bottom of the upper hull. I didn't have the tiny zip ties so just used masking tape (for now) to hold the wires together.
After I finished, I re-assembled the tank and tested all functions. It worked great!