"Apologies," Draco called back, gritting his teeth a little. Right, might be best to tuck that spell away for now.

He merely raised an eyebrow when Sasuke grabbed him, though, glancing briefly at the door.

"Cover me?" Did he expect this to take long? Assuming a simple unlocking spell would work here, anyway. If it didn't, well. Maybe Draco would have to break out that exploding spell again after all. Pushing that thought aside for now, he pointed his wand at the door.

"Alohomora!"

He was satisfied -- and relieved -- to hear the faint sound of something unlocking, and then he looked at Sasuke again. "There, done."