SA formations march camera perfect

[EngLearner]

Source: "The Third Reich In Colour", a documentary on YouTube (timestamp: 00m00s).

The narrator is commenting on what's going on in the video:

Berlin, mid-August 1933, SA formations march camera perfect through the Brandenburg gate just like they had done the previous January in the night when Adolf Hitler seized power.

Would it be correct for the narrator to use the continuous aspect in this case and say "are marching", or is the simple present "march" the only correct choice?

 

[emsr2d2]

The continuous would work too. Note that there should be a hyphen in "camera-perfect".

 

[EngLearner]

I just realized that the sentence is half in the present ("march") and half in the past ("had done" and "seized"). If I were to express it in the past, would both "marched" and "were marching" be correct?