Nico and her team of technicians took off the moment that they were given clearance to take a shuttle to the Envoy's ship to do the work on the Warp Drives.
They would be starting with the runabouts and the other smaller vessels which used the same sort of drives so that they could prove their competence and the reliability of the human method of repairing the crystals and tuning the system before they ever laid a hand on the main ship's systems, but that was no deterrent to them.
In fact, Nico might have lost a bit of respect for the Alliance's intelligence if they had let some random technician dive straight into the most sensitive system on their ship, the one that could guarantee their return home and the life support systems of their vessel.