If he throws it there in your pic, he gets rocked and possible gets deflected. Not good.
Here's the play.
Fields had to avoid the rush before Herbert turns his head and did a great job throwing it. He cocked his arm earlier and pulled it down to buy time because Herbert had just begun to turn his head when the rush was already on Fields. He was ready to throw it earlier but saved the play or at least helped it be this successful and he still clearly threw the ball 2 sec into the play.
Here's
Football 101: Screen Pass
"Typically, you wait about 2 sec. to throw that ball",
And to those complaining about linemen downfield, check where they are on passes in this video. It's always been a lenient part of officiating if not a blatant infraction.