Maybe Ripley’s arms are made of fire?

Amanda? More like Ash

In what was probably an alternate ending to Alien: Isolation, Amanda Ripley looked down and noticed that her arms were fire. How she went through decades of life without realizing that her limbs were constant chemical combustion wasn’t important right now. What was important was sauntering up to that damned xenomorph and punching it square in the mouth and the little mouth, too. She’d punch it so hard that it’d scamper up into the vents and never dare come out again.

That’s what presumably happened as soon as this clip ended.