Definitely a valid scenario but a few questions.
Witnesses heard screams in the park and others heard her shouting even before she met PR, so she was inclined to shout that night. Why did she not scream before entering ORPF?
Some people question her ability to make it to the river from outside the park because of her drunken state, she was described as being very very drunk and in a state. Also if she did choose to run into the park herself how did she avoid running into the open section and being spotted on the cctv overlooking the park, considering she ran in the other direction (near the playground) how did she not fall in the large pond instead?
Also if this was the case and she fell into the river accidentally, and PR knew this had happened, why wouldn’t he just admit she fell in the river and possibility admit the rape as this would have meant a lesser jail sentence than being trialled for both rape and murder.