There's two ways they did this
a. they replaced the Alien with the Neomorph (unlikely)
b. they jump-cut to them leaving right after the android kung-fu (removing Oram's death beforehand, perhaps cutting before he enters the chamber leaving his fate unknown) and jump-cut AGAIN to the ending scene (so basically they assume the crew has left unscathed). That way should be around 20 minutes or so of cut footage