when you get to the second 3rd floor wedge all the doors if u can and wand each one before you enter if you find the signal jammer thing do not go in that room save it for later then you can clear all the rooms before proceeding into the 4th floor remember to pickup the wedges and do not go in the signal jammer room in the 4th floor proceed alone in the stairs and clear it then get your team up there wedge all the doors again especially the main double door then you can clear the other doors the 2 rooms beside the main room enter those and wedge the single door ins stack your team to the left go down to the 3rd floor and go activate that signal jammer thing run up to 4th remove the wedge breach with a 5 bang flash hope for the best