First off, cut off and barricade any and all stairways leading into the second floor and have the already armed guards and civillians keep watch. The rest of the group is unarmed, so we would sweep the floor for any acceptable weapon and/or resources. Then, I'd find a room with a large enough window to allow us through it. We would barricade the door and any other entrances and post one of the guards by the door in case any of the infected got through. If the rope was sturdy and long enough, I'd tie it to a stable surface and throw the other end out of the window to allows us to climb down. Even if the rope doesn't reach all the way down we would only be on the second floor. If any materials like fabric were available, I'd throw them onto the floor to soften the fall and minimize the noise of the impact. The remaining two guards would descend first to scout the terrain, once it was deemed clear, the civillians would be next (armed ones first) and then the medic, as they are invaluable and would need protection. Then myself and, at last, the remaining guard would climb down.

From here on out it would all depend on how long ago the SHTF event happened. Are there still functioning cars we would be able to hijack? More importantly, is the outpost isolated enough that the roar of an engine would not mean death upon arrival? If we had to walk, the priority would be to get out of the city, even if the outpost was in another part of the same urban zone. If it was at all possible to circle round through the country and reenter the city only we we got within close proximity of the outpost that would be the ideal. In any case, if we were to move on foot, we would try to keep formation as much as possible. Two guards at the front of the group, one at the rear. Any unarmed members, and especially the medic, would be kept in the middle. Seeing as the outpost most likely has provisions, raiding would not be a priority, so we would take as little detours as possible to reach our destination as fast as we could.