From what Tony understood, Donnie should have been uniquely positioned to gain some understanding of the mechanisms of this door, and maybe knowing definitively that it was there was something of a win, technically. Maybe he'd be better prepared when he came around to his magic thing more. It was sounding to Tony like that was an important part of the equation, muttering, "Extradimensional maybe. Occupying a plane of existence we don't know how to sense yet." Even Jon's All Seeing Eye wouldn't work if something wasn't visible.

The battle shell was a welcome distraction from yet another problem Tony didn't know how to solve, and he enthused, "What--finished, like you built it in there?" He wasn't about to doubt a herculean creation under extraordinary circumstances, but couldn't imagine that would produce the ideal form that Donnie had been fixated on. So they could focus properly on these great strides, he flapped his hand to belatedly insist, "Don't worry about me, I'm always okay, I'm invincible," then raised the other still holding the boots against his chest. "I got you something. Do you know how to skate?"