MacBook froze installing macOS High Sierra 10.13.3 Update

I've had a gray screen/apple and progress bar showing 1/8th completion for 3hrs. And to top off the afternoon, Apple phone support just disconnected after holding for 30mins...grr...but prior to the hold, she was concerned that I wasn't seeing the customary countdown timer that's visible with some Apple updates. I told her, as best as I could recall, it wasn't common to see timers for the majority of the Apple prompted updates on my MacBook Pro (2000 17") and iMac 2013. Unfortunately...she was troubled and had to put me on hold for 30min 'to see if there was something that could be done' - until the dreaded - click. Surely, she'll call back because she asked for a tele# 'in case we get disconnected'....not.:( And while I was on hold with Support, I installed the macOS High Sierra 10.13.3 Update on my iMac. It restarted w/ the gray screen & apple, then zipped through the progress bar - and once again NO timer. The only problem - I didn't write down my Apple telephone support case # before I shutdown Safari for the Update...ugh. Soooo...is it as bad as the rep suggested...and would you recommend I try another bite at the phone support apple??? Or could it be as simple as shutting my old girl down and waiting 30 seconds? For now...the fan has also been running for a few hours and won't shut down.:( Appreciate any assistance....THANKS!