He doesn't swim naked, so he takes the summon anyway.
And Cam flaps for some distance and makes a high-speed atmosphere-friendly shuttle around himself and zooms away, chasing after scared evil aliens.
Eventually, though - after many, many planet-lengths, a distance that approaches the legitimately astronomical - it becomes clear that there is an edge to this universe. And hovering in midair, very close to that edge, there is a portal no bigger than an ordinary doorframe.
The aliens stationed at the portal are frantically shooting down all their own ships that make it this far, flashing emphatic lights to warn them away.
"Hey, did you know that the universe has an edge. With a fucking door in it. WHY IS YOUR WORLD THIS WAY."
Then: "...It looks like the edge of a Sphere. A very large Sphere, to be sure... but that's certainly a portal."
"It's... not impossible, I suppose. But I can't imagine how old this person must have been when they died, for their Sphere to be this enormous."
"Well, your universe has a door and that's how the evil aliens are getting in. Any guesses what I'll find if I rush it?"
"Another Sphere and portals to more, I expect. And more of the Enemy. Until you track them all the way back to where they came from, wherever that is."
"If the owners of both connected Spheres are dead, the portal is permanent. The owner of this Sphere must be dead, or we'd all need their permission to create portals out of it; I find it hard to imagine that the owner of the connecting Sphere might be alive, given that their Sphere has presumably been totally overrun by the Enemy."
"Well, that's inconvenient, I guess I have to follow them home. If you would like to check the inter-sphere-ability of these communication devices by stepping briefly into your own Sphere that would probably help, although my bet is that they don't work between spheres."
"Yeah. Probably applies to drones trying to talk to my computer too. So I'll go through and if I don't come back and say something in... two hours... assume something's gone awry?"
Cam wraps himself in stun shield and guns the engine for the portal. He may or may not briefly turn off the communication devices so that he can produce a ridiculous war cry in the process without being overheard.
Well, the ship's unprotected, he was mostly using it for momentum. Does momentum work in this weird physics sphere? WHEEEEEE.
He replaces suit bits as necessary. Adds a layer of force shields. Adds a jetpack. Zoom.
Once he's close enough to get a good look at what they're shooting at him with he shreds it, interpolating it with air.