Wow, thats tricky situation, for sure. Im just thinking, say, for argument's sake, if this was regular Gaia appliance (not smb), what @G_W_Albrecht suggested makes total sense to me as well. Because, say after box is back up after 45 minutes, then looking in logs might not show you at all why it took so long, so having it reviewed it via console access while its rebooting seems like the best idea.
Not sure at this time what TAC may suggest you do, because, even if they RMAd the appliance, well, if there are power issues at that location, who is to say that new box wont have same problem say 3 months down the road.
Just my 2 cents...