I honestly don't know what I would do. My general proposal would probably be to tie/chain up Sephex and any others who may come forward as possible infected. I'd rather err on the side of caution while still not needlessly killing someone who isn't infected. I'd hope we have an agreed upon radius drawn out from the tied up folks which no one can pass except for those designated to bring food and water. If possible, the tied up folks would be spaced so that should someone for sure turn, one of the other tied up folks doesn't get caught up. Take notes on if the condition worsens or disappears over a couple of days, and then let people go when they don't turn and improve in condition.

Of course, the other problem lies in just how exactly the virus spreads. Yes, someone gets bitten and they for sure turn, but could it follow the rules of some zombie fiction in which anyone who dies turns into a zombie after death?

As for rationing food and water, designating how decisions are made, ownership of weapons, etc. I don't know. Things will get difficult being trapped inside a warehouse. Power struggles will happen. People will get restless. One person not coming forward about being bit and then turning could spell death for everyone there. I'd personally want to try to find a way to sneak out without causing a stir with the people and zombies, and move away to where there would likely be less population.

Another personal note, I would try to extract blood from those tied up to keep in a syringe or whatever in case that person turns to keep on me. Someone I know had this conversation with me where they said jokingly that they would probably eat people before they ate dogs and cats. If I were to end up with cannibals, I would inject myself with the infected blood so that I could take them all with me.

Edit: We should probably also set Atilano's Mexican Restaurant on fire if any of us escape, just in case they actually were the start of the virus.