When you take only the lines that have the letters mentioned, do they look like numbers?

The safe locks and unlocks based on time, not a combination. You are trying to figure out a three digit time that the safe opened, and a three digit time that the safe closed.

Tracing out the lines of the letters in the report tells you the safe opened at 8:30 and closed at 8:32.

Yes, the safe was left open by the thief.

The thief knew that the safe would open automatically at 8:30, so they came here with the wrench to unscrew the secret panel and get access to the safe at the right time.

That information can be found in another room.