Master Chief force field are strong enough to take a missile and survive. A few moments later the shield was back up again.
Also if John gets injured, his suit will automatically heal him by injecting himself with Biofoam, which is said to be able to temporarily replace muscle, organ, skin and other tissue easily, even allowing them to perform in battle as if their injury didn't happen for hours on end. Thank's to YourNeighborhoodComicGeek for that info.
1- Scan- A young John just got hes enchantment done to him no armor. He see things in a slow motion, does the math in what time the pin hits the floor in mere moments.
2- Scan = This is John without Mjolnir Armor and he just got some alteration done to hes Buddy. Able to dodge bullets at point blank and make dents in titanium armor. They can run at burst of 34mph and he will get faster as he gets older. Lift 3 times hes body weight and that will be double thanks to there increased muscle density.( A average Spartan has been able to move a monolith made out of stone with a arm blown off.) Reaction at 20 milliseconds and will get faster in combat ( Armor will increase all stats by 5, In combat even more and Cortana will increase reaction even farther).
3- Scan- First time with the Mjolnir. His arm can move so fast the John wasn't able to keep track, and wood of turn he bones to dust if he bones weren't reinforce. Can easily punch true concrete. Stood still and let rounds deflect off the armor and dodge a couple without trying.
4- Scan- Will in combat situation, John see train armored soldiers moving slow way too slow. Is able to Easily break there bones my simple motions and taking them all out without killing them.
Chief is all around better super soldier.