But you are allowed to use whatever you can get your hands on when someone is literally trying to kill you.I don't want to go their but it'd be like having a gun as a kid. You're not allowed to use it, even if you've received training, but you could actually literally kill someone for real. Laws exist for a reason.
On the other hand, a rather good point by Spacewolf, it could be Eraser is just thinking ahead, or trying to make 100 % certain noone is holding back in any way.
Else, im behind the general consensus on Bakugou giving an explosive finger to any recuitment attemt that dont start with a massive knock to the head.