My main thought is, What did you expect?
Ravens are a good team with an offense that's tough to stop and the steelers were down 2 DBs then Porter got injured too so they're down 3 DBs. This isn't Madden where you sub in the backup and they do everything right. In real life backups make mistakes. Trice has barely played in the NFL.
The steelers have a plan for Lamar. Keep him contained and make him make plays from the pocket. For that to work, you have to have good coverage. You can't have blown assignments time after time.
With all that going wrong, Steelers still had a shot to win. If Russ didn't fumble, I think they may have won. That was the turning point.