Holy crap this is dumb as hell. Not you, your scenario. Gotta ask, did you even try to think this through? Fear mongering is not the way to justify additional tracking. Even if it was, your scenario is... holy crap dumb as hell.
So much wrong, where to begin. Let's see, did the driver nicely ask you for your phone so you couldn't, I don't know, dial 911 when you realized you weren't actually headed to your destination? Did they hit you with some knockout gas, chloroform you from the driver's seat, put on their gas mask and spray you with mace to incapacitate you...
Okay, forget that part. Let's get past the made for TV movie drama and look at the facts regarding the additional 5 minutes of tracking.
1. It's location data tracking. GPS. Not video. Uber would have no idea what transpired in the 5 minutes of additional tracking. They would have location data, that's it.
2. A customer is no more or less safe if Uber knows their location 5 minutes after the ride ends. It's not like Uber can prevent something from happening by simply knowing the location. Not unless Uber has Pre-Cogs on staff.

3. The 5 additional minutes of tracking only gives Uber an indication of the general area where the passenger is located when the tracking stops not where they're going to be if they need another Uber.
Hasn't Uber always known if you got to your destination or not? I'd imagine if people weren't reaching their destinations Uber would be out of business. 5 minutes of added tracking has nothing to do with
getting to your destination. It's a continuation after you're already there. If someone takes an Uber and closes the app when they get in the car, the tracking would be for an additional 5 minutes. What if your trip takes 10, 15, or 20 minutes? Are we back at the fear mongering stage now? OMG, they don't know where I am
Face it man, the premise of addition tracking increasing safety is inherently flawed. Even in your rape scenario, the passenger wouldn't be safer because of the additional tracking. It's just dumb.