The buggy he drove has added features such as plastic roll-up side windows to guard against rain and mud and a heater.
Once the finished vehicle is test-driven, it will go to a battalion called Crimea for use in reconnaissance missions.
Musa has given up medicine for now and feels he can help the war effort more through the buggies.
He is a Crimean Tatar, a Muslim group from the peninsula that largely opposed Russia's annexation and has been harshly punished.
Russians "hate freedom," he said.
"I want to (go) back to my home. I want to meet my family and it's my internal motivation to do this."
'Frankenstein vehicle'
In another workshop in Kyiv's outskirts, mechanics are also at work for the war effort -- on armoured vehicles for medical use.
The project is spearheaded by Romanian volunteer Radu Hossu, who raised funds among Romanians and Moldovans via his Facebook page.
It will provide state-of-the-art transportation for a medical battalion in the war-hit eastern Donetsk region.
Hossu hopes it will then be reproduced more widely.
His team is creating a complex of different-use vehicles to work in tandem, costing around $165,000.
They include a hybrid of a Ford truck and a Soviet Gaz chassis that will become an extraction vehicle to remove wounded soldiers from frontline areas even under fire.
It will be heavily armoured, with huge wheels.
"This is basically a Frankenstein vehicle -- it doesn't exist on the planet," Hossu said.
A Polish bus has been rebuilt as a mobile hospital where medics can immediately do complex operations.
Next, a former food truck is being converted into a medics' sleep and wash area.