Is your BIOS configured to boot without keyboard?
(I assume it is at present)
After that, it doesn't matter what is in the grub configuration as long as there
is a timeout (even if 0, which can make fixing some errors harder).
The system will come up. The references to initmode 3
are to disable the default of starting X (initmode 5). This is set in the file
/etc/inittab (change the line "id:5:initdefault" to "id:3:initdefault").