Practice, Repetition, Memorizing, Timing. That is how you will beat this. I literally got 6:30 about 20 times. I have heard its easier with the gun you get with the game however I never bought it, so I used the controller.
My tips, Always hit the elk so the bear comes out! You dont have to shoot the bear, its like free time that gives you a chance to breath. Also, Maximize powerups, max ammo and stopwatch are your friends!
Here is a guide I found on on X360a. Credit goes to Bodigard
I got the "I Will Survive" trophy early this morning and if you are having any problems here are some tips:
1. aim under the chin of the wolves (leads to a one shot kill with HEARTSHOT);
2. memorize where the wolves come from;
3. hit the 2 caribou in the camp site and then the 3 that run in the next area (will unlock a bear sequence that will last about 15-20 seconds with 0 chance of getting hit);
4. in the area right after the camp site wait until you are about to change areas and there will be a wolf that has an unlimited ammo power up, grab it and unload in the next area and build up your health early;
5. finally, the first rotation kills only take 1 shot, the next 2 shots, and so on so forth. so learning to quick shot and reload is a huge skill.
Here is how you should run through each area
CAMPSITE: Hit the first two wolves and let the first 3 wolves go by, the next set of three will either come from the right or 2 to the left and 1 to the right. Now the ducks should fly out, hit the one with the Marksman Power Up (nuclear symbol), hit the 2 Caribou that pop up and unload in the same area to kill 3 wolves....move to next site.
HILL: Immediately kill the first wolve on the right and then move to the left and unload quickly to kill the 3 Caribou. There should only be two wolves that pop up so quickly hit them. Now a bear will appear and as long as you are aiming under the chin you will waste some time killing it with 0 wolves attacking. Now after the bear is dead prepare for 3 wolves to come from the left and and right. Finally keep an eye on the right side for a chance to kill a wolf that has hte unlimited ammo power up. move to the next site
DOWNHILL: We are now aiming downhill. You will see 2 wolves go left to right, hit them quickly and then one from the left will arrive. Take him out and then you will see 2 Caribou run from the right to the left (one has health so grab it if necessary). There will be about 5-8 more wolves that appear. Once you see a lone one come from the right aim to the right to hit the one behind him for more health. Move to the next site.
TREELINE: Immediately aim mid right to kill two closing in wolves and then aim to the left to kill another set of 2. Stick to the left side as the wolves will spawn there. When you see a multitude of Caribou stampede look for one on the mid left to carry health grab it. Move to the next site.
RUINS: Quickly shoot 3 wolves on the left side and then aim to the right for a wolf with the unlimited ammo. Use it and get the one that is hiding the in brush to the right and unload in the middle of hte screen any wolves that show up. With the unlimited ammo none of hte wolves should get near you.
NOW YOU START OVER AND IT TAKES 2 SHOTS TO KILL THE WOLVES. Just repeat the above-state guide and you should last the full 7 minutes. It will take practice but once you can memorize and anticipate where they are coming from you will get the hardest silver in the game.