I don't see anything wrong with the event above; you have dt in the correct place.
I've wondered before about what would happen with C2 games on a 120hz monitor. What do you mean the game is 'going bandanas'? Is it running too fast, too slow, dropping frames?
My understanding is that it's problematic to 'sync' frames in browser engines when the monitors refresh rate differs from the refresh rate of the game. So, TLP is probably 'ticking' 120 times per second on the 120hz screen.
It's possible that you have some logic that should be "*dt", but isn't, and you've never noticed before since C2 goes apesh!t under ~40fps anyway, especially when GPU limted.
Unfortunately, we just don't have a good way of doing framerate-dependant or framerate-locked games in C2; to do so you have to eschew most of the built in behaviors entirely.
For example: CC had a setting called 'Override Delta Time' which would slow down/speed up the game when running at less/more than the intended framerate.
This is basically what you get in C2 if you do event based movement and don't use dt; the game speed is variable, but collisions will always happen the same given identical settings.
However, none of that applies to the built in behaviors in C2, whereas in CC it did.