Rescue Console is a feature available within mPanel to all customers at no charge. It allows remote access to a VPS from within a web browser, even when your VPS is otherwise inaccessible.
How it works
This feature is implemented through the use of an HTML5 or Java-based VNC client, that communicates over SSL with your VPS host server.
Because the connection is to the host, and not your VPS itself, Rescue Console will work even if you accidentally firewall yourself out of Remote Desktop/SSH or your VPS is unable to boot.
What its for
Normally, you will want to access your VPS using the standard remote access of Remote Desktop Connection or SSH. If you are unable to do so, you can use Rescue Console to correct the problem (and hence "rescue" your VPS).
Because VNC as a protocol is relatively primitive, it is best to use SSH or Remote Desktop Connection for normal operation. In particular, VNC is noticably slow at showing onscreen changes and your mouse cursor movements tend to slightly "lag".