Xorg server not to take virtual console at all?

I'd like to do some single-stepping in ddb to debug
the graphics driver and I was wondering if there is
any way to start Xorg server without taking any
virtual console at all?

I am using this to tell nvidia to use the external
HDMI port only (DFP-0 would be internal LVDS connected
display of a laptop )

Section "Device"
     Identifier     "NvidiaRelaxed"
     Driver         "nvidia"
     BusID          "PCI:1:0:0"
     Option         "ConnectedMonitor" "DFP-2"

hw.vga.textmode=1 in /boot/loader.conf allows me to stay
in the text mode upon boot.

This gives me a blank ttyv on the laptop screen, but if
I switch away from it via Ctrl-Alt-F1, external display
gets blanked as well.

I managed to get almost there by using:

startx -- -ignoreABI -sharevts

This way I can have a pure ttyv* to break into debugger
and work there. But this has a major disadvantage
that both share the input device (external USB keyboard) and whatever
I type goes into both the X server and the ttyv screen.
Typing Ctrl-C in the xterm can nuke the X server for example,
I worked this around by switching to another ttyv away (not the one
with the Xorg process).

The more I think about it - maybe it is really more
an input problem - "where should my keystrokes go and how do I switch"

I'd like to set hardware watch on some data in ddb so the switch
can be sudden and unexpected.

Marcin