Windows Bootcamp stuck in infinite boot loop
Had the exact same problem. 


Created a Windows 10 bootable USB using the Media Creation Tool. 
Once done, insert, switch the mini on, and when you hear the startup tone, immediately press and hold the alt key on your keyboard. 
Select EFI Boot. At the prompt, choose No. 
Select Language to install etc etc, then click Next.  
Don't click Install Now. At the bottom left, select Repair Your Computer. 
You might be asked to choose your keyboard layout. Choose UK or US, whichever is quicker. 
Now select Use Another Operating System. 


You should see several options, select one. If it doesn't work, repeat above steps, and try the next and then the next. 

Should you eventually end up successfully booting into Windows, RUN > CMD. Type msconfig and hit enter. Find the problematic boot records and remove them. Be very careful not to remove the one that actually boots you in. 

If you're successful, pause for a moment, and then take your time at thanking Microsoft for nothing.