Access to shell during or after kernel panic?

[Mick mtn]

FreeBSD 11R on macbook pro.
does not see dvd, yet the system was installed via
FreeBSD-11.0-RELEASE-amd64-dvd1.iso
----------------------------------------------------------------
partial panic printout:
module visa failed to register: 17
kbd0 at kbdmux0
Panic Module_register_init
CPUID=0
...
...
...
#1 0 . . . kdb backtrace           at 0x67
#2 ...      vpanic                       at 0x182
#3          panic                         at 0x43
#4          module_register_init at 0x11c
#5          mi_startup                 at 0x118
#6          btext                          at 0x2c

uptime 1s
-----------------------------------------------------------------
I can see the files in the rescue directory, but can not move to that
directory or issue commands like rescue/vi -v boot/loader.conf

ANY HINTS on possible keyboard combinations to force boot from dvd?
Holding "C" on boot is not getting the result i expected.