Through a series of fortunate events, the PCs were storming through Gralhund Hall. They made it past Urstul without much trouble and got Orond to spill the beans. And they had helped the guards defeat the thugs in the second-floor foyer. While the guards were grateful, they were also concerned about the PCs since they didn't know them. I had the guards stand outside the door that led to the bedroom that contained Lady Gralhund and the half-orc because they were being cautious and wanted to protect the lady of the house.

The sorcerer in the group rolled high on a persuasion check so I had the guards eventually let the party into the bedroom to talk with Lady Gralhund. Keep in mind this is AFTER Orond spilled the beans. They also checked the nimblewright detector, which had stopped moving and suggested that the nimblewright had split. Still, they persisted and talked their way into the bedroom--even though they all had burned through nearly all of their first and second level spells. As they talked to Lady Gralhund, they let slip that they knew more than they should about her operations and that the City Watch was NOT on the way. Because the party was surrounded and because of what they said, it would make sense that Lady Gralhund would order the attack. Which I had her do. Then, the same sorcerer bursts out a line about how she wouldn't want any more harm to come to her family/house, and I decided to give the sorcerer a persuasion check--which was the only check I gave the sorcerer in that conversation. The player rolled incredibly high, and so I had Lady Gralhund suddenly think about her children in the next room and claim she couldn't risk any harm coming to them.

The whole time, I was worried that a battle with four veteran guards (combined had more hit points than the party did) and the half-orc, who alone had more hit points than the party, would likely lead to a TPK. I figured that Lady Gralhund if her forces won a battle like that, would have no reason to keep anyone in the party alive because they knew too much.

So, I have two questions.

First, would a scenario like that, with the party a fighter, cleric, sorcerer and bard (all 3rd level extremely low on 1st and 2nd level spells), have likely ended in disaster if they were surrounded by four somewhat wounded veterans, a full-health Hrabbaz and Lady Grulhand?

And second, could there have been a better way to handle that situation? I feel like I gave them a lot of outs to not have to storm into the bedroom, which I think would have ended very badly.