I am stuck on a platform just after Darth Vader fled the room with the high vents and the two astromech panels. There is a narrow stairway and we are on a platform across from another platform where two storm troopers keep shooting at Luke and R2. Darth Vader is behind them doing nothing. We destroyed the one other thing on the platform releasing a minikit. Luke keeps deflecting their blasts and killing them sometimes doing a double shot that appears to kill both of them simultaneously. Luke cannot jump the gap and R2 cannot hover over it.

What should I be doing?