Well yeah ... Not only that but I find it hilarious he thinks he is the boss. Boss of whom? He isn't strong, nor do many people actually follow him, like if he gets messed up those other 3 are gonna just turn tail and run.
All of them are getting surrounded by those monsters and the men in black are even in the scene watching from the airlines to see whether they would need to finish off Gantz's players once the battle's over.
Even though it's Reika, she really knows how to be a badass when she needs to. She probably starred in some action movies beforehand or watching Kurono that intently might have taught her a thing or two~