Goofs

When Barry is flying through the air faster than the speed of sound, he has his right fist raised. When he actually hits Girder, he strikes him with his left.

Barry, when told he has to strike Woodward at 837 mph, says that he's never gone that fast before. However, he previously told Joe he could run a mile in three seconds, which would make his speed 1,200 mph.

Ripping out a fire alarm pull station will not stop an alarm once it has been tripped.

Cisco tells Barry that he would need to be travelling at Mach 1.1 when he hits Girder. Dr Snow replies with that's 845 [ish] miles per hour. That's faster than sound.

This converting to mph to then work out that it is faster than sound is redundant. Mach 1.1 literally means 1.1 times the speed of sound.

In the end, flash needs to run a distance (5.3 miles) specific to the decimal. Cisco first tells flash is exactly 5.3 miles away. After this flash does not run in a straight line to avoid obstacles. This would surely account for at least 0.1 miles more in distance. Since the math had to be accurate to the decimal, flash clearly didn't run the exact distance.

When Iris and the Flash are talking in the coffee shop, two policemen knock on the glass doors behind Iris. Although they can see Iris, they do not see the Flash, even though there are lights on in the shop and he is silhouetted against the light coming through the large windows of the door behind him.

At the beginning the Flash talks to Iris and she says "it's crazy what you can do to your voice". As she has always heard him talk that way there's no way she can know he's "doing" it and that it's not the way it normally sounds.