I was playing some capture missions for a lich when suddenly I was able to melee consistently during Mesa's 4. After some testing in the simulacrum it seems that if you Bullet jump up + Melee mid air right as you activate the 4th ability you can melee and still use peacemakers as usual lol. I believe it to be a bug but who knows! I tried it with Mesa's Waltz on and off and while you can do it with or without it, it definitely is a lot smoother with it equipped. I have uploaded a video on the Warframe subreddit and the link is here:
