I've got a question for you guys.
Today I GM'd a game with seven players. We're all somewhat new to DH, 4 of us have played a few games before (And are experienced players of other RPGs), while 3 were completely new. It was going pretty well and everyone was having fun, but I have one player who tends to get argumentative. It wasn't a problem until he nearly got himself and another player killed (perhaps even the whole party).
The group was tasked with taking down a hive gang that had connections to heretical artifacts being smuggled into the city. The player in question (a psyker) and a Scum had gotten in close with a few members of the hive-gang and convinced them to talk to the gang leader and let them join. The gangers led these two to the gang hideout and found the leader. The rest of the party followed behind them and set up outside the hideout just in case. The hideout itself is an abandoned office building that's 4 stories tall.
When they entered they were led to the second floor. The first floor had 8 gang members milling about with various weapons, and the second had 9. One of the gang members talked to the leader, they went into another room. The Psyker overheard the leader berating the member, obviously not pleased about a low-level member recruiting random people off the streets and bringing them to their hideout. When he finished the ganger leaves sporting a new black eye and tries to usher the two out of the building.
I expected them to leave with no problem, but the psyker started causing problems. He immediately starts insulting the gang-leader (who is in another room) and the gang members just sitting around (who are armed). The Scum (Who's face was, admittedly, priceless) desperately tries to get the psyker to leave with him, but to no avail. As the psyker continues, the gangers start getting agitated and the psyker decides to make the wonderful decision of using wall-walk to "mess with them". After successfully using it, he hops on a wall. The gangers panic at the sight of witchery and attack. The scum starts asking me if he can burn a fate point to prevent the fight, which I reluctantly declined, as it was the psyker's decision to instigate it. At this point, the entire party starts offering to burn one, and trying to get the psyker to burn one. The psyker stubbornly refuses, stating that "We can take 'em", and refuses to listen to reason that two people armed only with pistols and other concealable weapons have a slim chance against 9 guys packing shotguns and autoguns. He says that the team outside the building will run in to help (they have microbeads and were listening to the whole exchange), but then doesn't realize that it'll take a while for 5 people to go through 8 and get to their floor.
After roughly 5 minutes of shouting, the pskyer finally relented and burned his fate point, and the Emperor pressed rewind.
After that lengthy explanation, my question is this. Should I have let them "take back" his mistake?
If it was just the psyker's ass in the fire, I would've let him die. But the fact that he was dragging the Scum player down with him, and relying on the rest of the party to fight 17+ gangers (not counting the guys on the third and fourth floors) to save him made me really hesitant to let it happen.
Should I have just let it happen as it happened?