I assume they rightfully predict that you will just need to get faster if you want to do your whole workout and get back before the punching begins. Start to get worried if Samantha only waits 10 minutes next time, as that means she's controlling the situation very carefully.
Where does 11 minutes fall on the spectrum of restraint? Is this a new PR for Samantha? Perhaps you could go game theorist on the munchkins: if you don't get a phone call from them before x minutes, they get a small reward? Or you could set up the prisoner's dilemma and watch them both betray every single time.
How long before Samantha becomes responsible for a motor vehicle?
11 mins is on the short side. They have certainly done better and worse.
Luckily there is a ways to go before either of them could reach the gas pedal.