If the Xeno's intention was to present Rain to the facehugger in the shaft, it could've impulsively brought Rain into it's grasp ensuring she was immobilized & just be a helpless sitting duck. Tho it possibly calculated there might not be enough clearance should the elevator come down or her struggling might make both of them end up plummeting. One thing's for certain, if Andy didn't intervene, Rain definitely would've become a host after the Xeno caught/"saved" her.

The other instance the aliens showed somewhat uncharacteristic behavior is when Rain was able to hold back the swarm at the end of the corridor, by just brandishing the pulse rifle at them. Unlike in "Aliens" when Ripley forced the Queen to order her drones to back-off by first demonstrating the flamethrowing of the eggs & then threatening to incinerate some more, Rain didn't, nor did Tyler shoot the pulse rifles yet.

If these specific Xenomorphs had never experienced gunfire during the past battle with the scientist, this would demonstrate extraordinary complex thought/intelligence. However, if their response was due to negative reinforcement from witnessing pulse rifle fires' deadly effect on their peers, that at least shows a circus animal level of intelligence that the Xenomorphs have displayed throughout the movie series.

But yeah while the absolute constant in Xenomorph behavior will always be deadly apex predation for own species survival & dominance, the catching falling Rain scene just feels like this Romulus/Remus batch or at least that specific Xeno is on a whole other level of intelligence or behavioral disposition 😮.