Yes it's because there was an injury they got a much bigger fine as they endangered personell...
"
The incident was the second of its kind over the weekend for the Finn, who was also forced to stop in second practice with a loose wheel....
Having reviewed the incident, the FIA race stewards in Bahrain handed Ferrari a €50,000 fine for releasing Raikkonen's car ‘in a manner endangering team personnel and causing injury’...
Bahrain marks the third Grand Prix in the last four seasons that Raikkonen has retired from as a result of unsafe release. An unwelcome statistic indeed" (from F1 website).
Think Ferrari need to be looking at their pit procedures and the system for giving the driver the green light. They clearly need to make improvements to stop this from happening again.
Maybe the pit system is one of the things Haas purchases from Ferrari