Sil Vs Quinn
There were two outcomes between the situation with Vorden and Quinn. In Vorden's head, the best outcome would be for him to ask Quinn to put his blood in the flask kindly. If Quinn were to question why, he would simply tell him to trust him, and he would inform him about the details tomorrow.
However, knowing Quinn, he would try to get involved some way or another. On top of that, he would try following him. If the first part of the plan worked, then Vorden would hand the flask to Layla while keeping an eye on Quinn, making sure he didn't leave the room until everything was done. Hopefully, this would all lead to avoiding him fighting with Quinn.
Then again, Vorden was someone who always needed to prepare himself for all of the possible scenarios. There was a good chance that when asking for his blood, Quinn wouldn't do so without saying why, leading him to forcefully take the blood.