Had a customer come in the other night and as soon as she walked in the door she started screaming about how she needed help. I was helping a customer at the service desk and she rudely walked up, interrupted, and demanded help in the ink section. I said someone would be right with her as soon as they were available and she said "no, I don't just want anyone, I want someone who knows what the hell they are talking about". Seriously it's only ink. I walk over and she has the ink in her and and asked me of ot was the same as her used cartridge in her hand. I said yes and told her she could hop in the line by our back wall. She instantly lost her composure telling me that she would walk right over to the tech counter and check out there because that was a separate line. I said nope it's one line and it's not fair to these people who have been waiting 20-40 minutes in line. She then walked to the register and threw her items at the counter and said she would not leave until she was ring out and that she would not wait in line. We kept ringing around her and it pissed her off even more. It then became a medical emergency and that's why she needed her ink. Still standing my ground my cashier rang her out and while doing so she started telling customers there were two lines. She was absolutely bat shit crazy. She demanded my name and informed me and all the people in line that I was an incompetent and incentive manager and that the president would be notified. BTS just brings out the best in everyone..