My truck carries multiple/layered survival kits. There's a 96 hour kit for just hanging out and there are fixings for a couple walking kits. Urban/suburban/wilderness -- just doesn't matter. If I go to the desert (it isn't that far) I take more water.
If I had to leave the truck in either wilderness or urban setting
(think SOCAL post major earthquake urban), I'd load up one of the hydration packs and start walking. More likely though, I'd get comfortable and wait for things to settle so I could drive out. If it was a just me serious survival situation, I'd go into one of the packs and pull out a PLB -- then I'd do something appropriate like wait.
As for urban vs. wilderness, SOCAL may not really be urban after a major earthquake. With that in mind, my truck kit is wilderness oriented and my EDC takes care of urban. Wherever I go in urbia/suburbia, the wilderness kit is pretty much within a short walk.
As for multi-tools -- I have the Leatherman Supertool 200 as a glove compartment tool -- very handy and very capable. (ST300 is supposedly better(?) whatever that means with nearly indestructible tools.) I skipped the Blast and went bigger for my truck. For my belt I wanted to not carry tools I never used (thinking urban) so went with the
LM Fuse, it's lighter without sacrificing tools I actually use. I tried the slightly lighter LM Kick, but I like having scissors and I didn't like the Kick's lock. I also have a LM Skeletool CX hanging on my larger backpack and a LM Charge TTi buried at the bottom of my EDC backpack. I think I'm covered for MT's.