So, I finally went to the construction tour that SFM is offering to their visitors and it was very nice!
During this tour, you can walk through the Medusa structure and see some of the work that they have done. Also, they give some interesting technical facts to GP.
It's important to note that this tour is offered only when there are not workers in the area. If you go to the park Monday-Saturday and if you are lucky, you can enter the tour around 13h-14h. Sundays is almost sure you can enter the tour between 13h and 18h. All depends on the works on MSC.
Enjoy the photos!