Maybe a little quick but not really. The horn started blaring when the truck crashed, which would have been shortly after he was shot dead. Spencer was trapped in that building for who knows how long before he got to the truck. There are cuts between different scenes after the truck crashed so we can't really tell from that episode how long it took. But when you watch the following episode you get a better idea of how long the horn was blowing.

 

Yeah, it was the driver. Even 5 minutes would seem like forever with that racket, and people can turn in as little a 2 minutes. It did seem fast, but not anything that couldn't be explained. The Wolves were all really dirty, so I think that might explain why he didn't look "fresh".

 

Nah, they probably just let the walker drive in the first place... They can't be killed easily, and even then you only loose one of your walkers. All I wonder is, why were they dragging that truck there in the first place? Their plan did not seem to include walkers, or if it did, no one seemed to act as if the truck crashing had any effect on their tactics... Just a bit of an odd standout for me, as they seemed to already be doing what they do.

 

The truck was probably going to drive through the gate. The back of it may be full of walkers, it may be empty, waiting for loot/torsos/etc.

 

I don't think he was alive either. The Wolves are dirty but that wouldn't mean he looks this decaying already.