You could try the somewhat dangerous: taskkill /IM cmd.exe
..dangerous bcz that will kill the cmd that is open and any cmd's opened before it.
Or add a verification to confirm that you had the right cmd.exe and then kill it via PID, such as this:
set loc=%time%%random%
title=%loc%
for /f "tokens=2 delims= " %%A in ('tasklist /v ^| findstr /i "%loc%"') do (taskkill /PID %%A)
Substitute (pslist &&A)
or (tasklist /FI "PID eq %%A")
for the (taskkill /PID %%A)
if you want to check it first (and maybe have pstools installed).