A vascular closure device includes a deployment assembly, a sealing unit carried by the deployment assembly, and a tamper carried by the deployment assembly and that is disposed along a suture with respect to the sealing unit. The vascular closure device includes a locking assembly coupled to the tamper so as to selectively inhibit advancement of the tamper along the suture in the distal direction toward the sealing unit. The locking assembly is adapted to transition from A) a locked configuration where the tamper is inhibited from sliding along the suture, into B) an unlocked configuration where the tamper is slidable along the suture in the distal direction and into contact with the sealing unit.