Successfully getting in undetected was only the smallest part of their problem; they still had to find Jasper's maker, hopefully kill him without drawing too much attention, perform a spell, and get out safely. It wasn't likely that every vampire had left the castle, but having a lot of them momentarily gone certainly upped the odds that they wouldn't be attacked by a horde. Wanda figured they could take on small groups easily, but if they were set upon by a large swarm then they might not make it out alive. "If anything comes along that we can't handle, grab onto me and I'll get us out," she promised her companions in a low whisper as they ascended the tower staircase. Better to retreat and fail than fight and die.
When they rounded the corner into a hallway they came face to face with a lone vampire who, after a half second of hesitation, charged. An energy shield went up around them instinctively and the vampire rebounded off it, looking dazed. Wanda took that moment to meet Jasper's gaze, her own wide in question. Chances were slim that the first vampire they'd encountered would be his maker (as if they could be that lucky). If Jasper felt nothing they'd take him out as quickly and quietly as possible then move on.