Section 4. Unless the defendant is the mortgagor or his assignee, or entitled to hold or claim the land under the mortgagor or his assignee, he shall not redeem the land nor have a conditional judgment, except with the consent of the plaintiff, but the action shall be conducted like an action for possession, and in all cases the judgment for the plaintiff may be entered for possession as at common law, unless one or the other of the parties moves for the conditional judgment.