It is not "dying" on this message. It is just disconnecting you from the SSH session because sshd daemon was shutdown in the reboot process. It is normal when rebooting through SSH (and for this reason should be avoided, cause you can't see if server came up after reboot). For remote reboot it is better to use ILOM, ALOM or XSCF (depending on your hardware) and do it from server's console.
messages were not sent through SSH - they were printed on a local terminal. And that's where the reboot process stops when initiated remotely (but at the same time, local reboot works fine).
I could have observed this because I currently have the machine at home and am just testing remote restarts.
which h/w are you using? can you do a "soft-reset" of the system to power cycle and see if you can see the messages. IT SHOULD reset, probe and bring your OS back. If not, how did you got the OS up again?