This was the first Shadowrun mission I'd ever run, and it turned out to be alot of fun. For me, at this point, the group didn't immediately comply when told to pull over, leading one of the gangs to start a high speed chase and shootout on the highway. The other gang showed up immediately afterwards. The two gangs looked at each other and silently agreed to take care of the runners first, and then deal with or fight it out with each other. One of the gangs got their vehicle trashed. Then the runners then started getting stuck in traffic with the yakuza still behind them. They decided to cheese it outta there before the Yakuza, more Triads, or Lone Star showed up. They then split off on foot, one phys ad base jumped off the highway (using a parachute). A mage ran the other way, eventually turning a corner, shapeshifting and then flying outta there. By then, I pretty much said they got away from the two groups, and they all met up again shortly afterwards.
I'm glad that this is the first mission I'd ever run. I realized right away that the reason it was so much fun was because the mission itself had a strict time limit of a couple hours. This kept the whole thing fast paced and the game moving. I was just giving our regular gm a break, but every session I run will have an in-game time limit for one reason or another.