Hi Bryan!
Thanks for reaching Microsoft Community. We're here to help and let's work on this together.
With your query, yes, you can power on your Surface Laptop 4 while it is docked to the Surface Dock 2 with the lid closed. To do this, you can simply press the power button on the Surface Dock 2. The power button is located on the top of the dock, near the front edge. When you press the power button, it will turn on your Surface Laptop 4 and any connected monitors.
Thanks again for choosing Microsoft. Hope this helps!
Regards,
RodelioP.