I'm not going to say it wasn't a risky decision. Since you had already guaranteed your safety in the performance— staying back to fight the monster could be considered as rash or irresponsible. But you saved Aracha as a result. So I cannot say it is any more risky than those who chose to not look behind.

Perhaps looked at another way, what would you be feeling now if you and Aracha had been devoured by the monster?