Pretty sure you don't actually need to take the quest to be able to enter the facility. Unless it's an instanced dungeon which this very clearly isn't since otherwise the two parties wouldn't have even encountered each other.
What are the odds that either one of his suicide rushes goes horribly wrong and he can't be healed, or his shitty attitude makes somebody decide it's time to "accidentally" have a friendly fire incident?
Bro he literally went from standing next to his wife and daughter to being within physical attacking range of your illusion in a matter of seconds. What makes you think that he's not at all capable of doing that again in the other direction at the same speed?