I do admit Christ's suffering was finite, but it was the equivalent of the eternal punishment for all believers. It is the Lake of Fire...the second death...we are saved from. And we are saved from it because on the cross our sin debt is paid and we are no longer under condemnation. This is why we don't suffer the second death. It can't possibly be physical death we're saved from because we all die physically.
And we are all raised physically so yes, physical death has been conquered. You don't seem to want to acknowledge that. The Lord's word was sin and die so there is no reason to raise men back to life except for the Cross.
The lake of fire is not the punishment for sin. You are sorely mistaken.
The reason we don't suffer the second death is because we believe in Christ's payment and His resurrection. We live because He lives.