When confronted with similar situations of being locked out of a MBP, I ssh login from another computer over the network. Once logged in I then execute the Terminal command: "sudo reboot", which restarts the MBP. This is generally better than just doing a "hard restart" by holding down the power button for 10 seconds since the reboot procedure properly closes down the computer and any applications that are running before restarting.
Good luck,
Solouki
P.S. Once you are ssh logged into the unresponsive MBP, you can also run "ps auxww" or "top -o cpu" to see if there is some process that is fully utilizing your CPU. And if you feel the need, you can also kill the Windows Server to potentially regain access to the unresponsive MBP without rebooting it.