I was driving and stopped at a light in neutral on my 2.0T 2007 A4 (6MT). Suddenly all of the interior lights go dark save the radio backlights and the tach is stuck at idle. The engine surged, the radio quit, and I got on the gas to make sure it didn't die once the revs dropped and to make sure I wasn't seeing things at night with a non-moving tach needle.

Upon getting the final two blocks home, I park and it won't start. I look for busted fuses and can't find any. I try to start it again and it starts, a little slowly, and dies after 1-2 seconds. I tried twice to give it gas. The revs climb past 2 or 3k (can't tell without gauges) and it dies again, super quick. Only did this twice.

I did a visual inspection and nothing seemed really off, though I'm not an expert. No codes.

I tried searching here and couldn't figure it out. Any ideas?