This is a quiet, timid, very Gregor-y way to illustrate the horrific incident of waking up as a "monstrous bug." This uncharacteristic reaction almost reminds me of disassociation, a symptom of mental illness where the afflicted person feels "out-of-touch" of reality, either being desensitized to outer stimuli or feeling as if their watching their life in third person (like a movie). Their movements grow mechanical; some might find themselves in areas that they do not even have recollection of going there. Disassociated people also react slowly, or don't react at all, because they cannot register that there is a reaction in the first place.