Monroville said:

I guess if there is one thing to add/note, I noticed that the ion cannon is firing as the transport ships are lifting off. Should we see a glimpse of the blue ion beam behind them or after the bigger one starts to move to the right of the ion cannon (as its in mid-recoil from a shot)? I'm guessing it's a mostly-finished shot?

You have to see the whole sequence to see what's actually happening. The Ion cannon is only powering up and getting into position as the transports leave