system
Given the following post, respond as if you're commenting on Reddit:
human
[Alien] In the original film, why is there a lack of panic and urgency in the crew when they discover the adult Xenomorph?

Saw the film for the first time recently, and it is a very good horror flick, especially for its time, though it was a bit too slow-paced for my taste.

Anyway, maybe I'm remembering wrong, but when they find out that an alien is on their vessel causing mayhem, they discussed their next move very nonchalantly. To be fair, Ripley was pretty freaked out towards the end, but I'm referring mostly to the 2nd act.
gpt
It's because of characters' characteristics - Ash is, well, you know who. Parker is "I don't give a damn" pragmatic brute. Ripley is "no nonsense" officer. Dallas is jaded, tired and "doesn't want to be there", grumpy captain. IIRC he is also a soldier, a veteran of war with actual combat history under his belt.

...and then there's Lambert - she is scared, panicked and already crying.

There's also the fact that the alien wasn't truly seen. Parker merely observes that it has to be big/huge. They are still oblivious about what they are facing.

In addition: it's assumed that people who leave Earth, spend years in cryosleep and risk being stranded among stars simply can't be that fragile.