stuck on kb3124280 for over an hour now

I've been having trouble for weeks with updates. Last week my PC rebooted after I tried to update and got stuck in a loop and finally reported that the updates failed. I previously ran the System Update Readiness Tool and sfc /scannow. I also used the Microsoft fixit to check for windows update errors (several times). After refusing to even check for updates again earlier today, this afternoon it said updates were available, so I checked them all and tried again. They all downloaded and installation began. Currently it's stuck on update 19 of 37 - kb3124280. I have no idea what this update does but my firewall asked if MRT.exe could connect to the internet. I allowed it and it's still stuck on kb3124280. The green progress bar isn't frozen so it appears to be doing something, but the HDD light stopped being active quite a while ago and now the updates appear to be hung up unless this update takes this long for some reason. Is MRT what's causing this to get hung up currently? I think this is the Microsoft Removal Tool and it's currently running according to my task manager but there seems to be no HDD activity other than some random blips and I have no idea if it's just scanning or if it's stuck. Is it the kb3124280 update that's stuck or MRT?

Any advice on what to do? I hate to cancel the update because I've gotten this far, but I can't sit here all night waiting to see what happens. What is this update it's stuck on?

Did SURT find any problems? If it did, you should repair or replace the missing/corrupt files.
The CheckSUR.log is temporary & located at: C:\Windows\Logs\CBS. If it's not there, you'll have to run SURT again.
If SURT didn't find any issues, I'd select all the updates except kb3124820 & install them. When you are not going to use your computer, like bedtime, I'd temporarily disable your firewall (if your paranoid I'd enable windows firewall) & start installation of kb3124280
Here's the MS explanation of kb3124280