Enter the room while morphed and let the hoppers jump against the wall a couple of times. Between hops, unmorph and shoot the lower hopper. Roll under the top hopper until it goes off camera to the left.

Entrance condition:

"comeInNormally": {}

Requires:

"Morph",
"canPrepareForNextRoom",
{"enemyKill": {
  "enemies": [["Blue Sidehopper"]]
}},
"canCameraManip"

Unlocks doors:

{"nodeId": 1, "types": ["ammo"], "requires": []}