come on! there was absolutely no guarantee they could predict that Dave Franco was going to be able to elude the police. Even with them magically turning him into Jason Bourne. What if the swat team was right there when he was started attacking? What if there was no fed car nearby for him steal? What if traffic boxed him in it is NYC for crying out loud.
Another of many plot holes. Actual law enforcement does not tip off suspects ahead of time (and one low-ranking agent would not have the authority shown) by cutting off utilities. They wait until agents are in place and then close in.
Also, low-budget garbage disposals can't continue to run with a suit in them.
Ignoring politics doesn't mean politics will ignore you.
-Pericles paraphrased in <100 characters

Dylan (Mark Ruffalo's character), the FBI agent who was the mastermind of it all was right there is all of it, and the whole point of him being on the inside of the FBI (spending years in that part of the preparation) in his plan was to make sure that the FBI didn't catch them, so he could ensure that Dave Franco's character made it out (remember he concocted the whole plan, including getting the black sedan and having the second sedan ready). In the story, he does it so well, he even fools Dave Franco's character (who apologizes at the end for roughing him up). Getting the radio and impersonating his voice to get the SWAT team to check other floors was likely also part of Dylan's plan in the first place, so he could ensure that there was an opportunity for that. The whole idea was that Dylan masterminded all of these details so that it would work out. Traffic can happen anytime, but there would be times of the day that would be less likely and alternate routes until they got to the bridge, so he would just have to be ahead of them enough for them to release the car. These things are not the least believable for me. The poor romance development and unlikely event of the interpol agent falling for buffoon version of Dylan's character is more unbelievable to me, and then there's the whole supernatural element of The Eye, and how the four of them were easily convinced to do all this (which they just skipped over in the story, but presumably the room that they showed up in the first place was magical enough/impressive enough for them to take it seriously, but still).
Having Dave Franco's character fake the death means that it made sense to everyone (including the public) that there were only three in the final magic act, so that he could carry out the rest of the heist with the safe, without anyone even following him because they thought that he was already dead.

So they would stop casing him I guess. N all their instructions came from that cop..(even tho they had no idea it was him)..he would have made sure how he could escape n that a car would be there at his disposal.