Don't need to install "ADB insecure"

[awilkins]

Since you have a root shell you can copy the file to a location that adb pull can access.

adb shell
# Now you're on the phone
su  # and do any auth action your root requires
cp  /data/data/com.google.android.apps.authenticator2/databases/databases /sdcard/Download/
exit
exit
# Now you're back on the computer
adb pull /sdcard/Download/databases

[duk3luk3]

You can also just run adb root if your phone is rooted and allows rooted adbd.