"When faced with a triggered conversation, there seem to be a number of things that take priority to it. Priming a grenade is one of them, and it allows you to nearly stop this encounter with Layla's gang. They normally appear behind you and immediately force you into a conversation, but this lets you wander anywhere inside the building until you release the grenade.

I believe the door is locked until the encounter is over--so you can't leave--but I could be wrong."