Sasha had both adrenal and insulinoma, but I'm pretty sure it was the insulinoma that claimed her life in the end. We went through a lot of problems with her in the last year of her life, and nothing we tried seemed to make any real difference. When it got closer to the end, she had a much more difficult time using her back legs. She wasn't very active and was way too heavy for her small frame, so I was never sure if it was the insulinoma or if she just couldn't support her own weight on the slippery laminate of their play area. When I let them out to play she just wanted to curl up next to me and sleep. She had troubles climbing in to the litter box on her own, and as she went she couldn't stand and ended up messing all over herself so I had to clean her and put diaper cream on her every time she went to avoid a rash. On her last day I found her collapsed on the bottom of the cage with a trail of poop and urine behind her. She tried to get to the box but just couldn't make it. My vet was about to close, and I just wasn't ready to let her go so quickly as time passed I realized I should have brought her in, but I hoped she'd stay with me until Monday at least. So I just held her in my arms and 5 hours later she finally decided on her own that it was time to go. That's why I asked about the staring in to space. It's an indication of insulinoma, and the crash you described reminded me of when Sasha finally gave up the fight against the disease.
I'm so sorry about Havoc, I know how much it hurts to lose a carpet shark. It's been almost 5 months now and I still miss her like crazy.