to get out of restricted lab go into the door on the right go up the stairs into the door
then when you hear the explosion go back down to the bottem room after the metroids kill
the sa-x space jump up to the top door. to get the purple suit [gravity suit] defeat the
securety robot the 2nd time.

You get the gravity suit BEFORE you face the BOX security robot. The BOX security robot
gives you the wave beam.