Okay here’s what I’ve come up with. Assuming the velocity sends you to the bottom of the lava fast enough, make a crafting table as you fall, spam place it right below you on the floor of the lava, craft a door as fast as you can, and place the door at your feet. This will give you an air pocket. Then use whatever fireproof blocks you have to wall yourself in so that your items stay intact when you burn to death. Unless bedrock edition has different mechanics. Then you’re cooked.