The next day I have the new part, and return to my lab... and the time machine has gone!

I search everywhere, and there's no sign that it left the room! Somebody must have used it! But it wasn't ready! Who took it? Where did they go? What will they do? There is no way of knowing where they went... forward? backward? Anyway, it doesn't matter now, as it would take me six months to build a new one, and what damage might have been caused by then? Is this THE END?

Or should I work flat out and create a new machine and test it? Or do something else?