At 1:30a, everyone is sound asleep tucked in for the cold night.it takes 30 minutes to get a tug operational from a cold start, not to mention the crew. I believe, the transition procedure in and out of port for large ships will require a tug escort, maybe 2. At 100,000 tons, 1 tug won’t be enough.
I don’t think the tugs all shut down at 5 o’clock and go home for the night at a busy harbor. I’m sure they have around the clock operations at port like Baltimore. The original story mentioned that two tugs helped get the ship out of its berth and into the channel.
Doesn’t mean either could have gotten there on time, but they were on duty.