Morbid as it may be, we need to find a guard's hand to get the cell open.
Most of the aliens we've seen so far have burst when killed - see if you can find a corpse that's a bit more than a blue stain.
The legs in the lunch room seem to imply that there's more corpse to see nearby.
Look up - there's a hand stuck to the ceiling.
That hand is a bit too high up to reach - for now, at least.
If we made a commotion, something violent, the shaking might knock the hand loose.
Ralf will probably be quite mad if he finds an alien soldier alive.
The prisoner told us that 'striders' have a great sense of smell, and return things to their owners.
Since Ralf is a strider, giving him one of the soldiers' possessions should do the trick.
There's one hiding in the geology lab near the lunch room - maybe he's got something we can take?
Remember, we have a locker password - and there's a password-locked locker in the geology lab.
Assuming you exhausted dialogue options with the prisoner, you can 'grab' the locker to input the password.
The scarf apparently belongs to the nearby guard, so show it to Ralf and enjoy the show.
The hand is still firmly stuck, but we can now access the rest of this lab - check it out!