Thought Goran Višnjić gave an okay performance as Nikola Tesla. Thought it was odd that this alien race would find a man from the early 1900s ideal for fixing their advanced technology (thousands of years ahead of him). Don't care how smart he is, Tesla would have no idea of what any of this stuff is. Let alone how to fix it. However, this is a The Doctor meets historical figure story. So, it has to play up Tesla as extraordinary.