The gun Sara is holding on Nikita as they drive away from the site of the explosion is not the same weapon she was holding before breaking in to the car.
Around the 27-minute mark, as Robbie is about to speak to Amanda, the hand that reaches in from off-camera doesn't actually turn the door handle, but you hear the latch disengage. It *could* be magnetically operated from a switch somewhere else, but that's less likely than the actor simply forgetting he needs to actually turn the door handle, if the prop door doesn't actually latch shut. (The sound effect could be added in post)