Deliberate mistake: There are several large security mistakes that were obviously added to the film to move the plot forward. The takeover of "Control" would not happen that way. The Secret Service keeps it in a secret off site location which not even the security detail knows. This location is in some kind of very remote bunker to prevent what happens in the movie. Secondly, when the threat is identified and the switch to the double is made, the President would have been moved to a secure bunker created for the purpose until the threat was dealt with.
Suggested correction: It actually could still be possible for a takeover of "Control" to happen even if it was a secret off site location/secure bunker. Depending on Taylor's security clearance and how high up he is in the secret service, he could have been one of the few in the security detail that knew where the secret location was. Since he's the one that got Barnes back on detail, he most likely has a high clearance.
No actually it couldn't be possible for takeover of control. No one in the security the detail knows where the secret location is. Even if Taylor had a high clearance it only grants access to a limited number of places. One of the places it doesn't grant access to is the secret location.
With a high enough clearance it could still have been possible. Not to mention there could have been more than one mole in the secret service other than Taylor who had the clearance to know the locations.
Read it again. "Even if Taylor had a high security clearance it only grants to a limited number of places. One of the places it doesn't grant access is the secret location." So Taylor would not have access to the secret location no matter how high his security clearance was.
Takeover control couldn't be possible if the location was an the location an off site secret bunker because the villains wouldn't be able to find it. Even if Taylor had a high security clearance he wouldn't know where the secret bunker because if he was ever allowed in there he would blindfolded to prevent him from learning where the bunker was. Taylor would get arrested if he learned where the bunker was.
Only the service officials know where the bunker is. Taylor is not a secret service official.
Deliberate mistake: In the point of view of the Hispanic cop, he is being led away by a secret service (SS) guy when the cop hears an explosion, he punches the secret service man but before the SS guy can react, the second explosion goes off. In all the other points of view, the first explosion goes off and there is 30-40 seconds of a break before the second explosion goes off. (It's clear the director needed the cop to have the distraction of the first explosion to attempt to get away, but in order for the cop to escape he had the second explosion go off seconds after).