So Hedin has been destroyed, and Omega has gained control of the matrix, the Doctor must escape Gallifrey to stop Omega's plan to transfer and return to Gallifreyan Society. The Doctor speaks to Tegan in the matrix and discovers their Dutch location. Omega begins to transfer, Nyssa and the Doctor are on foot seeking the location Tegan gave him. The Doctor's intervention is too late, Omega has transferred, but is he stable?
It's possibly the best of the 4 parts, it is so refreshing to see the streets of Amsterdam used as a location, the trams, the river etc.
I like the effects of Omega's transfer, it looks quite effective. Finally, the last of the Ergon, never to be seen again.
The scene of Omega stopping and enjoying the barrel organ is a particularly effective one, is Omega a reformed character?
There is a fair bit of running around, but at least it's purposeful, and not down corridors, there's lots of energy from all concerned.
The finale is a satisfying one, as we see the Doctor defeat Omega and save the day, and Tegan's back on board, joy.... for some.
Part 4 gets 8/10