Based on Moran’s rates (one of the two tug lines in Baltimore) that would cover about two movements per day. They charge $3100 per hour for escorting, two hour minimum, and you’d need two tugs (one on each side) to possibly handle sudden steering emergencies like this.
I couldn’t find good stats on the number of large ships passing under the Key Bridge per day but I suspect it’s more than two. I saw two heading out in less than three hours on Sunday (one cargo ship carrying new powerboats and sailboats, one cruise ship).
There are probably better things we could do for safety with that much money.