Honestly, the problem was that 4 members of the group went in black trenchcoat, only to discover that the fifth member had decided to throw the plan away and roll pink Mohawk.
Full story: A pimp contact of ours contacted us with the news that several of his girls had started acting oddly, and he was calling in a favor we owed him. our investigation led us to a drug dealer's house in Renton, and after a brief and successful recon we determined that within the house was a commlink that was somehow connected to the girls' odd behavior. We had floor plans, our hacker owned their security system (Though we expected them to reboot the moment they realized this), and there was a Lone Star station about three minutes out. The plan was simple: The hacker would lock most of the on-site security out of our path, prevent the system from calling backup, and hand control of their drones over to our rigger. The team would infiltrate silently, take out the guards with precision bursts of gel rounds from suppressed weapons, grab the commlink (and if it turned out the commlink was in the drug dealer's head, we'd kidnap and sedate him), then get out of there before the security system could come back online and sound the alarm. We knew that the guards were carrying SMGs loaded with gel rounds, and if we hit fast the situation would at worst be 1 street sam with full combat loadout vrs 1 or maybe 2 wage-slave security types. We spent about an hour planning the raid while we waited for the pizza to arrive, working out which guards could be effectively eliminated by our air support drones (packing sniper rifles) and which would be locked out of the fight. We had most of the run fairly well thought out.
The plan went well enough at first, with one guard disabled by our infiltrator, another three downed by their own drones (which were outfitted with ingram smartgun X's, again loaded out with gel rounds), and a fifth going down quickly to our troll's suppressed machine pistol. Then captain stupid decides: "Screw this stealth business" and blows his guard away with a three-round burst of ex-ex from his unsilenced shotgun. This is the point where he reveals to the group that he doesn't have any silenced weapons after all.
Worse, this guy was our point man, so he was going to get to the target first.
Now I was taking a turn at GMing, and I figured 'hmmm, everyone else has been silent, this guy is running up the staircase with a shotgun (Which raised the alarm early, by the way) and has obviously got no intention of being non-lethal... the wage mage lieutenant at the top of the stairs isn't going to hold back.' Captain Idiot runs up the stairs and straight into a force six power bolt, fails his will check, and takes a healthy 9 physical. (Yes we are using the optional rule about adding hits to the spells force for extra drain. the wage mage overcast for all he was worth and took 6 physical from drain). The guy beside him pounds the intruder with a pair of shots from his pistol, and the good Captain needs to use his last point of edge to avoid hitting overflow. He geeks the mage and the guy next to him, then runs into... the drug dealer's 5-year-old son's room. Nothing to do with the mission, he just decided that he was too close to death to take on the likely armed drug dealer so instead of waiting for backup he decided to go for a defenseless target. He announced his presence by busting open the door and shouting "come out little kiddie".
Now the drug dealer heard that and, having jumped out of bed and armed himself upon being woken by explosive shotgun fire, charges fearlessly across the corridor to protect his son. Captain Idiot takes a shotgun blast to the back and I roll, giving the drug dealer 12 dice. the result: 9 hits. Captain Idiot then blotches his dodge and soak rolls and goes into hand of god territory. With no time to think and no knowledge of what just happened (She was focused on taking out a particularly stubborn guard in the courtyard) our rigger switches to the alternate clip on her sniper drone and shoots the guy who had just KOed our team-mate. the alternate clip: Anti-Tank rounds. The drug dealer was still in his pajamas, and never stood a chance. The rest of the team rock up and I tell them that they have to decide RIGHT NOW what they're doing, there's no time to think and if they delay for even a single initiative pass Captain Idiot dies. They follow their first instinct of help a team member and manage to save him, but Lone Star are on their way and Doc Wagon have assault choppers already in the air so there's no time to search for the commlink (Note: I decided that to get him out alive they needed both of the other on-site runners to pick him and the medkit up and carry them carefully, in exactly the right relative positions. that meant no time to so much as glance around if they wanted to get out before the cops turned up. They did get a manservant drone to grab the dead drug dealer as well in case the commlink they were after was implanted, but it wasn't.)
Of course, not only was the mission a total disaster but Captain Idiot was quickly located by the authorities. Now it would have been through ritual magic (He left a lot of blood lying around, after all) but before the wage mages could do their thing a group member slipped the authorities the location of the guy's hospital bed.
End result: Captain Idiot was arrested and is claiming that he never killed anyone, it was all because the troll mage mind controlled him and set him up. While no-one believes his ramblings he has effectively compromised the whole group, the most paranoid of whom are only going to have to burn a SIN and get some minor cosmetic surgery while some of the others have to burn everything they own and everyone they know.
Oh, and this was the first time my hacker ever came on-site for a run... in fact, it was the first time they'd even met her in person. yeah, probably not happening again.
[ Spoiler ]
Though technically they haven't met her yet, as she just sent a Renraku manservant with mimic 3 in her place. The manservant has its own SIN, licences, lifestyle and identity (All of which I'm having to burn), but still, I think that it was a good call.