SO...what happens to Wrinkly Weyland?

POSSIBLE EXISTING SPOILERS IN THEORY....So Weyland is on his ship. A man in his position and with his ambition, having a choice of spending his remaining years on earth or being first to experience and get his hands on alien technology..well, it's no choice really. The David8 model on board is pre programmed for Weyland and is protecting the old man and his scheme. Weyland has made him more of an artificial son than a standard model. When they touch down and it's established that there is indeed a ship on the planet, David is tasked with deciphering how the tech works, including how to navigate and fly the vessel. The bio-helmet (complete with head inside) they recover is scanned, and from it, information gained as to how to replicate the technology. During the mission, tension flares between Vickers and David. Vickers is aware that her father seems to care more for his creation than her. Whilst chaos ensues around them with the crew that Weyland sees now as more expendable than useful, Weyland plans to be taken to the temple by David and steal the ship and pilot it to earth. He wants to be like Prometheus and steal the fire from the gods. He says as much to Vickers who warns him, " If you go down there, you'll die". Weyland has learnt a great deal from the impregnation of Shaw and the effects of the alien bio material on his human crew. Under the cover of all the fighting, David takes Weyland and fits him into the juggernauts pilot chair using the adapted helmet they have built using the advanced 3d printing devices on board (Weyland built of course). He's a little small for it..but they've made some adaptations and the chair "blends" with it's new pilot. At this point, as David is setting the path for Earth (having found the globe in the vast 3d star map)...the ship starts to launch, but the ENGINEER (a being created by the original SJ's, who turned on them savagely), which Weyland and David believed was occupied assaulting the Prometheus (something that David8 facilitated by letting it on board to finish off the crew who were wise to his plan), enters the chamber.... David has previously encountered the engineer in the chamber whilst examining the star map and in a spine tingling encounter, it chose (?) not to harm him...possibly seeing him as a non-sentient being, however, now as the engineer goes to attack Weyland in the pilots chair, David reacts to defend him and there is a short struggle during which Davids head is wrenched off. The remaining crew on the Prometheus, are now fully aware of the extent of Weyland's plan and know where the ship is about to head to. They know what is on board and that Weyland has used them all as expendables. They realise what will happen if Weyland unleashes the technology on earth and those on the Prometheus, most of them infected in some way set a noble suicide course to destroy the vessel. Vickers however wants to live...she doesn't want her hated father to be the cause of her death and so she takes one of the escape pods. The ships collide. The Prometheus hull is no match for the bio-mech ship, but it knocks it off course and sends it plunging towards the ground. The engineer falls during the collision, just as he was about to rip Weyland from the chair. He manipulates the controls in the room and the ships speed decreases as it wrenches itself from the gravitational pull and comes to a halt nose down. No idea beyond that except that....like the end of Alien where Ripley has to go around the ship to find Jonesy....for some reason Shaw and Vickers will go back into the derelict..possibly to find David....who may still be streaming them video. Possibly to find Weyland...or possibly because it's the only way off this rock....if they can kill the engineer......it'll be nerve jangling!!! Just my thoughts at the moment.....any comments?