Can a soldier go on a pass while on quarters (during AT)?

Background information: This past week I departed my residence on route to Annual Training. Approximately 10 minutes into my 2 and a half hour drive, I was ran off the road which resulted in an ambulance to the E.R. as well as a totaled vehicle. I had no major injuries and was discharged promptly. Relatively. My unit then sends 2 SGTs to collect me and medical paperwork and then proceed to AT. Once there I'm sent to TMC for a checkup. I am placed on quarters, hydrocodone, muscle relaxers, and told to report back in 2 days. When time for my follow up, I was ignored/forgotten about which resulted in the follow-up being pushed to the following day, despite complaints from me concerning my pain. At the follow-up, I was given 2 shots which where ineffective, at best, and told to return once again in 2 days. On the date of the next follow-up, I was told by my E6 that transportation was being arranged (myself unable to drive). Despite multiple reminders from myself, this wasn't the case and I was forced to make my own arrangements, my unit being to busy preparing for the field. TMC once again pushed medication without investigating further, treating only the symptoms with ibuprofen and muscle relaxers as well as another shot. I questioned this with the Lt. Col at TMC, insisting that be able to follow up with my civilian PCP instead. He stated that we would consider it in 4 days when I come back for yet another follow-up. At this point I was ushered out and sent back to quarters. I alerted my chain of command to this and then was left to myself with no guidance with how to continue. At that point, it was Thursday morning, my company was heading to field, and I began focusing more on my insurance claim. USAA aranged for a rental car to be dropped off on base, in preparation for the 24 pass we were to receive on Saturday. I was intending to use this pass to attend my sister's graduation, which I had consistently pushed up the chain of command the month preceeding AT. Once I Saturday came, I was told that I could not leave for 3 reasons. 1) I was on quarters 2) I was on pain medication 3)I should know better than to ask the day of. However, the only medication I was on that day and the 2 days preceeding was ibuprofen. Also, as stated earlier I had been asking for a month prior. They confirmed that I had requested the day for the graduation, the request had somehow fallen off before reaching the CO. They then requested the sick call slips to confirm the other portion of my response. This is the point that I get reamed. On my last follow-up with the Lt. Col. no additional notes about extending Quarters were written. My E7 then gets in my face calls me a liar, accuses me of avoiding going to the field, states the Lt. Col. knows what he's doing and wouldn't make the mistake, a says that I will be on every KP and weapons guard for the next week when my "story" doesn't check out, regardless of any profile. He then goes and checks and confirms my statements. Instead of apologizing he then demands the rental car keys citing that he wont risk having me drive off in the middle of the night. He also orders me not to step a foot outside my barracks except for medical emergency. So finally, here are my questions.

a) Does being placed on quarters for medical reasons prevent a soldier from taking a pass? To which the only physical difference, at least that I'm aware of, is conversing/seeing with family who incidentally haven't seen me since the accident.

b) Can my E7 demand my keys? Seeing as how I have given no indication of deserting/going AWOL, nor am I too impaired to drive. (Also the car needs to be returned and I am the only one authorized to drive it)

c) Do you have any recommendations on how to proceed with this situation? This incident seems to have become personal, and in my opinion, borders on harassment.

d) My E7 also stated that I should have informed them about getting a rental. I don't understand the logic behind that. Any insight would be appreciated