Turn off serial console on boot

[Chris St Denis]

I have some servers with IPMI that allow me to have a serial console. I 
have setup a serial console config on my servers and it seems to work 
reasonably well in remote emergencies, but causes serious problems if I 
ever have to use the real console.

It means that I can't use single user mode from the real console and I 
can't see most boot errors.

Is there a way I can turn off the console redirection from the physical 
console interactively on startup?

Running FreeBSD 7.

Console config:
---------------
barium# cat /boot.config
-DS19200

barium# cat /boot/loader.conf
comconsole_speed="19200"
boot_multicons="YES"
boot_serial="YES"
console="comconsole,vidconsole"