His mind already raced ahead after the yes, planning the exact order he needed to use in order to open the hexes. He didn't need to break them, which was the tricky part. Breaking them would have been easier, do each one and worry about the next after. But even if they were able to cast the hexes again in the same order, Rosier wasn't an idiot. He would have been able to tell someone else had.
"Presto," he replied to answer Theo's questions. "It shouldn't be too hard for me to hold them open for you once I have it open, but I won't be able to do anything else." Holding his other hand out to silence any questions, he focused on the hexes. No reason to waste time. The first couple were easier, but he had to hold them open while getting past the others. Zach held his breathing even, not letting himself shake at all.
Once it was done, he waited until he felt he had it, really had it, and could hold it. "Okay, it should open," he said.