That's what is sounds like. He accosted her, and either blocked the route home (to her mom's house), or she carried on running out of Brooklyn unaware that he was not giving up.
"Rivera admitted to
making contact with a female running in Brooklyn and that he
pursued her in his vehicle in an area east of Brooklyn, Poweshiek County, Iowa. "
http://media.graytvinc.com/documents/082118+DCI+Arrest.pdf
If taken literally, it almost sounds like Rivera made contact with Mollie in Brooklyn, perhaps at the Boundary/Middle Str. location. Then he pursued her in his car as she ran along 385 Ave.
Regarding:
she made him mad and thus the "block" "memory" problem, did he get mad after he made contact, and then he pursued her with his car? When did she allegedly threaten to call police: at the time that he made contact, or when he was pursuing her in his car? He had enough socialization in Iowa to know that pursuing a woman with a car is going to lead to calling police. He can't very well claim that he didn't expect that.
If she made him mad when he made contact in Brooklyn, did he not have enough time to come to his wits before he pursued he in his car?