Don't worry about the timer since its only there to freak you out. You'll notice how shaky your controls will become, as an effect of the gas. Once there, protect Viola as she searchers for the parts to fix you up. You can also find friendlies there you can recruit for additional firepower. After pushing the second container out to the water, you need to head to the nearby Rim Jobs to fix your mask's damaged hose. There's a brute there so prioritize in taking it out. Kill them then head to the second container. Push the first container to the river then head to Viola's position. You can start by taking one of the Enforcers in the roadblock behind your starting point so you have faster and meaner means of travel. The zombies are also fast so you incendiary weapons will do wonders here. Use the Sonic Boom to push the containers and keep them intact. Take note that you should be careful not to blow the containers with your guns or its mission failed. As you work your way to the containers, I suggest switching to your conventional weapons to keep the undead away. Once inside, you'll have to submerge the containers in the water to neutralize them. Drive first to the mayor's office to start the mission.
