Imaging without a write blocker

If you don't have a physical write blocker you can use a registry key for USB to write protect those. If you don't use a blocker at all odds are some dates will change, but other than that nothing else should change.

You could try to boot into PALADIN and mount the disk as read only and then image the disk. Obviously you will want to use a write-blocker when possible; however, like you said it is for educational purposes.