Bruce's approach of the door didn't falter, but he did spare a glance toward the floor where the vial had shattered and the blood spilled. 

Something in Vale's voice changed- subtle, but not impossible to detect. This gave Bruce momentary pause, if only because of Sakki's curiosity. 

Bruce slowed his pace- he kept quiet, but he was giving Vale an allotment of time to give him an actual reason not to proceed immediately.