You are on the turn after your Lv.4 landed: Dobermon is standing on a Salamon, they passed and the gauge opens at 3. A Dark Field and an Orochimon are already in your trash from earlier self-trashing, which is what makes Cerberusmon worth digivolving into now. Your hand is five, and the second Dobermon in it is the card you are going to throw. They have a Level 6 and two Level 4s out, and five security.