Super-considerate, too! Dude thinks of everything.
Note there are two conditions: IF he goes mad AND he endangers the world. If he goes mad and just decides to fly to Saturn and skate on the rings, that's okay.
The real problem is the hole in the wall he left, exposing the Oval Office to penetration by unfriendly elements, but he'll probably seal that up with Super-Bricklaying Skill on the way out.
By the way, if you were the President, this wouldn't make you uneasy. At all. No sir.
"Any reason for this, Superman?"
"Uh - no! None at all. Just - no, no reason, I was just . . . "
"What, Superman? You trailed off, portentiously."
"Did you hear that? I keep hearing these voices. Telling me things. Well, it's probably my super-hearing, an attribute I have because of Earth's lower gravity. See you around, sir - and say nothing of this to the Masons."