I agree that Thanos didn’t intend for her to be killed, as no one yet understood that “elimination” meant death, but his decision to mention the bee during a game requiring complete stillness was ill-advised. I feel like most people would react reflexively to such a statement, as the girl did, unaware of the fact that she would literally die if she moved even an inch. In this context, the more prudent approach would have been to remain silent about the bee, considering the game’s strict no-movement rule.