The illegality doesn’t seem to bother Eren. He’s too busy rummaging around in his bag as they head for the bike to pay the risk much mind.

"Great. I've been wanting to ride it anyway," he says, finally finding the potion he’d been looking for. He uncorks the top, takes a fair sized gulp and offers the rest to Heiji. "Vampire Toxin," he says shortly, wasting no time with further explanation. He doubts Clara will need the protection, but Heiji might.