Deadpool certainly wasn't expecting a giant Tony Stark to bust in and start helping out with the battle, but he won't say no to the assist. When the mech suit throws himself in front of Deadpool--in front of Deadpool!--it makes him laugh out loud. Has Tony forgotten who he's dealing with here

"Thanks, sweetheart!" Deadpool dives between the mech's legs and comes up with a gun in both hands, aiming them right at some monster faces. "You get a bullet, and you get a bullet! Everyone gets a bullet! Ooooh, fireworks!
Do it again!"

Yes, he likes those energy blasts.

But Tony doesn't do it again, because he's caught in some vine things. Deadpool holsters the guns and draws both katanas.

"Get ready, Disney! Deadpool's coming in for the save!"

And then he dives on the mech, slashing away cheerfully at the plants.