Alright, so, Boothill and Mei get through the projectiles via lot of dodging and blocking with those shields. Boothill even has to grab Mei and dips her like a couple dancing for one particular projectile.

Then, they move on to the room with the lasers. Boothill tests the lasers and see that the metal shield and his hand get singed but it seems to take a very long time otherwise for anything troubling. So, Boothill suggests to Mei to use his body as a literal shield along with giving her his to help better protect her.

Boothill gets out of this with more marked up metal and some uneven hair getting singed at the ends and Mei has some singed clothes and some laser burns on her skin. But otherwise, they seem to be okay.