Billy had just started to explain to Queenan that he could get no more advance info about Costello's drug orders when his phone rang. Much as he wanted to ignore it, that would be unwise if it was anything to do with Costello's increasingly demented want's. The message that came over the phone stunned him. Billy grabbed Queenan and said "Run, the gang know we're here".
Once in the lift, Billy hit the button for the second floor, "Costello put a tail on you ... unless The Mole did. We go out by the back - they could be here anytime".
"Only a Staff Sergeant or higher can do that, officially" Queenan replied, horrified by the implications.
Once at the second floor Billy sent the lift back up to the 6th floor and they went out by the fire exit, which he slammed shut after a brief look around.
It took some time for them to work their way around the building and as they emerged onto the street, Billy could see a car just in front of the entrance, with a car plate that he recognised. Carefully moving forward he saw the last of the gang heading into the tower. Billy said "Run", and they both bolted across the street and down the nearest connecting road.
The surveillance cops watching the entrance from their car down the street were just digesting Sullivan's command that they stay in place when they saw Billy and Queenan bolt like terrified rabbits across the road. They could see that Queenan was in trouble, and reported into Control that Costegan and Queenan had fled the site.