276,000 MPH is quoted as the presumable top speed at which the Resolute's structure can remain sound. At this speed it would take well over 10,000 years to reach Alpha Centauri, rather than the 5 years quoted in the show.
The colonists enter a cave, in which they expect to find the planet's apex predator, armed with... pointy sticks. Even if they didn't want to create (more) deadly weapons on their printers, they could at least have created some non-deadly ones, like shock sticks, or phasers permanently set to "stun".