Purple can be a lot of things. Since you got no error it would be almost impossible for us to guess. A staff member will be along shortly and they can look at the logs and see exactly what happened and help you understand.
It’s probably safer not to use it again until you hear from a staff member.
In the meantime - if you have that situation again you can open the lid, tape down some aluminum foil over the part that was already done, close the lid and hit go. As long as you don’t move your material, or the laser head, it’ll print in the exact same place - and since it can’t cut through the aluminum it won’t re-cut the sections you’ve covered.
It won’t save any time, but it will allow you to “restart” your design.