After you exit the house and get bags of explosives to blow up the bridge, save the game. This is the first timed mission, which you have to complete in under fifteen minutes. 'Bridge Across the Dnester': Easy completion.You will be able to get near the helicopter. Do not bother to kill enemies in order to save time and avoid tanks. Walk besides it up to the end of the mission. When you reach near the river, you will be able to see the red line (not to be crossed) and 'Danger' and 'Mine' symbols.
Press Z two times to crawl and make your way to the river. Use the Map Computer to find the river and the best path to it.