Thank you very much for the details.
I suppose that I will need VPN access in order to be able to power on the Gateways.
The problem is that the VPN access runs through this cluster.
I am thinking to power off (soft) the one (A) of the devices just to be safe and sure that the one of my devices will not have issues from the power outage. The other device (B) will stay online until the power outage and will become "up" when the power recovers. If (B) is up with no issues, then I will have access to LOM in order to power on device (A).