When Duncan stops to see if he can help Sindy, he looks in the mirror and sees her unzip her outer garments to show off her red top (and, presumably, what's inside), but when she gets to the window, the purple vest she is wearing under her outer coat is zipped all the way to the top.
When Duncan is looking into his cabin using the thermal camera, he can see through the windows like the glass wouldn't be there. This is not how thermal camera works, as it would only show the temperature of the window glass and not through it. If the thermal vision would show through the window, it would do so through the walls, too.
The owl is obviously a captive owl, as the noise it makes are 'baby' sounds which young owls make when begging for food. Mature owls that have grown up in the wild do not make this noise as they have learned to hunt for their prey and do not have a need to beg for food.
When Duncan is shooting his way out of the mansion, he engages multiple guards in a narrow concrete tunnel. Firing a handgun or submachinegun in such a place without ear protection would have rendered him completely deaf in his *other* ear as well.