Gru needs to reach the exit. The path to the exit is blocked by a red platform that flips up whenever the red button is pressed. Reaching the red button is tricky, as there's a rotary valve in the way.

Gru orders a minion to stand next to the rotary valve. He blasts it with the wind gun to make it float.

Gru jumps up to where the blue button is. The button controls both the rotary valve and a blue platform.

Gru presses the blue button. The rotary valve rotates and the blue platform flips down. The floating minion can now be pushed into the rotary valve but it's blocked off by the blue platform. This isn't doing any good.

Gru steps off the blue button. The blue platform flips back up and the rotary valve rotates again.

Gru orders the remaining minions to form a wheel next to the floating minion.

Gru uses his wind gun on the minion wheel to get it spinning like a fan. The floating minion is now being pushed forward.

Gru steps on the blue button again. The blue platform flips down but that's okay: the minion fan blows the floating minion into the rotary valve.

Gru steps off the blue button. The rotary valve rotates and the floating minion floats up the shaft toward the red button.

The floating minion hits the red button. The red platform flips up.

Gru drops down and can now exit the room.