medication error

Could you please help me with this? I'm an lpn & I was training a new nurse at an alf at a morning med pass. We're both at the cart, I have the keys, the cart is open, she's pulling meds for a resident. As she's doing that, I told her I would pull the meds for another resident who was getting ready to leave the dining room. I give her the meds and when I come back to the cart (the cart is in the dining room with the tables surrounding them) she's already pulling another one...I wait beside her to initial for the meds I had given. I did not want to interrupt & confuse her med pull. As I'm waiting, a resident life manager & security manager come beside us (this happens too much when we're on the cart) and asked me a question about a recently deceased resident's family whom had caused a ruckus the day before. In order to protect the family's privacy, I followed them into the office to speak in private. The office is about 10 steps from the med cart, around the corner. I excused myself from the orientee & probably was in conversation for about 8 minutes. When I returned to the cart, a second orientee had arrived & SHE was now on the cart and had already administered medication to maybe a couple of other residents, one of them, the one I had already given medication to, hence a med error (double bp meds & baby aspirin). Apparently, orientee #1 had told orientee #2 to go ahead & administer medications to the few that were left. According to orientee #1, she did not hear me say, I gave the resident her medications. Analyzing what went wrong, I of course said I could've made a greater effort to initial the meds. Perhaps lock the cart when I walked away (although orientee #1 was there). I could have probably communicated that she should have waited for me to come back to continue the rest of the residents (I never thought she would continue on her own, not knowing the residents, let alone, instruct another new nurse to do so when I wasn't present). Thank God there were no ill effects from the med error. I spoke to them both & apologized for my part, but also told them neither should have continued without me being there, as I'm the one orienting them. Now, when I informed our director of health services, he mostly expressed his concern about orientee #1 & her delegating to orientee #2. He said only to verbally speak to her - not an official counsel. I for my part, asked for better guidance from nurse manager as to a plan for me to train two nurses at the same time (my first time doing so) from then forward....fast forward a week later...a disgruntled employee- not a nurse, finds out about the error & plots to take pictures of medical records & report this error & others to the state. The day after she got fired, the state comes in to investigate. Now, our director, wants my manager to write me up for the error. I just would like to know if your audience (or someone from your staff) believes this is appropriate. Should I be written up? & if so, wouldn't the orientees also need to be written up? Does it only fall on myself? Are they just trying to have a scapegoat? Please comment. I would appreciate it very much. Thank you!