No, he enters the Gym, drops the mask and stays there, until the dust settles. He's in disguise, and as far as you know Mort, it's a good one. So the guy won't be in any danger, since he's there only to fool the lookout...
And he just wants to send a message. How strong it will be, it's up to you. The animosity between them is already over the top.
If you want to get some cannon fodder to finish up, you can call Mort and tell him that. If you can provide them with a place to hide before you finish your part, he'll be okay with that.