You can see it in the speed trace. Piastri's carrying momentum out of the hairpin, late on the brakes into Turn 6, still squeezing the throttle through Turn 8. Stroll's driving the same line he's been driving for 40 laps — tidy, consistent, a second slower.
This is what giving up looks like when you're contractually obligated to finish the race. You don't bin it. You don't park it. You just… drive. Stroll went 18 laps on the medium before pitting. Piastri went 17. Their strategies were nearly identical. But by lap 40, when Piastri briefly took the lead from Leclerc, Stroll was already a minute behind — and the final gap of 67 seconds tells you he never tried to close it.