i do not think delete /var/db/mcpdb.* or touch /service/mcpd/forceload works in appliance mode.
there are two enhancement IDs for listing/renaming/removing file in appliance mode but /var/db and /service/mcpd are not in the directory list. i am not aware of other method. you may open a support case to see if they can add /var/db and/or /service/mcpd directory to those IDs.
ID425460 - Appliance Mode: Need a way to list, rename, and remove core files in TMSH
ID350895 - Appliance Mode: whitelist SCP directory access, whitelist (or disable) sftp access
hope this helps.