If you happen to have NFL+ you can watch the replay. At the 2:00:55 mark the replay shows the head ref announcing the "rule" that it couldn't be challenged. and the feed cuts to a close up of Harbs talking to someone in his headset. You can read his lips, but it is pretty clear as day he says "I fudged that up". Straight from his own mouth. So the post-game lie was just him saving face, instead of admitting a mistake. Just like the strange manner in which they closed the first half final possession, then quickly called a TO before the FG to save the Rams some clock. Granted, the risk of them trying anything significant is small... but WHY???
Which is the truth, he effed that up. Emotional, super fan, hype man John Harbaugh doesn't manage to stay focused on the rules, the clock, the score, timeouts, the important little details that can swing a one possession game in the final seconds, etc. He wasn't paying any attention to his timeouts, and how having all 3 might help give them another chance in the event that last drive stalled before the endzone. Nope, he was desperate and let his emotions take over, decided to hail mary the red flag against all reasonable hope.
Now say Lamar doesn't connect with Flowers with 1:16 left. They run another play and come up short, the Rams have the ball back with about 1:10 left in the game. Now, with 3 TOs left, a 3 and punt could give the Ravens one more shot in solid field position with about 45 seconds left. With only 2 TOs left, a 3 and punt could give the Ravens one more shot in solid sitld position... with about 5 seconds left.