It might have been tight to do twenty laps on the mediums, but opting for the hard tyre didn't provide that much of an advantage. After all, Verstappen's hard tyres were 'only' about eight laps older.
Ferrari was thus very conservative and that did not ultimately work out as hoped.
The safety car entered the track at lap 50, while the field was only released five laps later.
Ferrari's reasoning is understandable, because the removal of Yuki Tsunoda's car at the exit of the pit lane indeed took a relatively long time. It took some ten minutes just to salvage the car, as repair work on the guardrail or wall was not necessary.