That sounds like another unfortunate accident for the family. V-tech and lawyers fight harder against each other than any other faction pairing, all you need do is look at the PvP videos to see this. The Family have a bad habit of ending up getting accidentally pincered by lawyers/vtech before they charge at each other.
These are not co-ordinated strikes, even if they seem like it. If you weren't camping a building, you may have been better off. As Simms said, mobility is important.
The rare instance of lawyer/v-tech teamwork -- and I can vouch for this as I was there (though I do not condone score-whoring, if this happened, it was before I showed up) was due to the platoon that left v-tech and went to family a few nights prior to when this happened. There was bad blood between us and that platoon, there were little to no v-tech online willing to ZC, and given the options, lawyers winning instead of them seemed like a good choice at the time.
The enemy of my enemy is my friend.
There are no rules against co-operating with other factions. Lore-wise, the Lawyers and V-tech are neutral, as are family and BB, v-tech and family, and lawyers/BB.
The core is what we make of it.