On this stage you will fight with Magneto and Sabertooth. Iron Man is disarmed, so you can rely only on Hulk and Wolverine.
Defeat all prisoners to open up another chapter of the fight - that's your chance. Choose Wolverine and approach to the pile of bricks located on the right, then build a green handle from the debris. Lift object using Hulk and throw it at Sabertooth. That's the end of the first round.
Second sequence is quite similar - defeat all minions, then build another missile, throwing it at the target.
The last sequence looks nearly the same - but this time you must build not one, but two objects and throw them at Sabertooth. Notice that arch villain will jump from the destroyed platform to the other one - that's the reason for two missiles.
After that, the fight is over.