Feeling ambivalent about decision

To provide a little background, I am currently a junior (2 semesters remaining) and am currently on the pediatrics unit for clinical. I had a somewhat difficult day yesterday, as my 7-year old patient was quite complex. The day culminated in a moment where my clinical instructor asked me to retrieve a soiled diaper that I had erroneously thrown away earlier from a biohazard bin in order to weigh it. I did make two attempts at retrieving the soiled diaper, as I certainly did not want to tell her no. Unfortunately, the diaper was so deep in the bin that I would have had to submerge my entire arm (up to top of my rotator cuff) to retrieve it. I suppose this just felt completely unsanitary and more importantly unsafe to me in that moment. I decided that I simply didn't feel comfortable retrieving it. My plan was to communicate my concerns with her before she had to ask me about it. However, I was so busy and overwhelmed by the tasks of caring for my patient that she followed up with me about it before i had the chance to approach her. I told her that I was unable to retrieve it, as I felt uncomfortable with the idea of submerging my arm up to the top of my rotator cuff. It is very possible that I misread her, but she looked a bit perturbed. It may be worth noting that the patient's orders did not include an order to weigh diapers and when I checked the chart, I found that only one diaper weight entry had been recorded since admission. However, I made sure not to repeat my mistake and saved the subsequent diaper for weighing. Maybe I am just neurotic, but my question is, was it wrong of me to tell my instructor that I was uncomfortable retrieving the soiled diaper from the biohazard bin? Did I make the wrong choice? Should I have retrieved the soiled diaper? Has anyone else had a similar experience? :-/