I guess it's just bad luck that the explosion occurred exactly when the firefighters entered the underground car park. My guess is that this was 10 to 15 minutes after the initial crash. If the explosion happens a few minutes earlier, at least one of the two firefighters who died might have been saved.
There were four firefighters inside and three of them got out, but one went back in to try and save his colleague. Those were the two that died but another was critically injured - I'm guessing it would have been reported if he hadn't survived? Very sad.