The ideal skill tree is Technician with Breaching Charges, you would want to take 2 breaching charges with you (for blasting the bars open) and a key card scrambler. You would then start the run. Shoot down the ladder and window and hack the PC knock out the employee as fast as you can and then bag them up and use the disguise. Then run to a key card door and hack the door, if it the server room search the computer, if it's the guard room knock the guard and take note of the power box. Then go to the other key card door and hack it. Do the same here. Re-wire the power box and get the disguise, run over to the sensor and disable it, then quicky hostage the manager and open the vault, blow up the doors and put the bags in the van via the sensor door. if all goes well you should be able to have a run around the time of 4:30 mins.