If you get right down to it, there are two ways John Constantine spends his day: either in immediate peril or out of it. (Although arguably there's also having just gotten out, and about to get into, but split that many hairs and we'll be here all day.) His appearance in the entrance chamber seems to indicate the former, both of which have their pros and cons. In immediate peril (he was) means now he's suddenly not, anymore, or at least not in the same way, but out of it - well, those moments are few and far enough in between that he likes to keep them for himself, thank you.
This moment: not shaping up to be one of those.
The prelude to this entrance is a rush of wings and a strange, inhuman clicking; the air ripples and warps and snaps back into place, leaving a tall, lanky man in his mid-thirties, dark-haired and dark-clothed, with the kind of pallor that actually takes some work to maintain in, for instance, southern California.
Maybe he's a vampire - just kidding. The dying implosion of air stirs a black coat open with the sleeves rolled up, the ornate tattoos on the backs of his forearms somehow alive like the oscillation of wind across water. "--to the light, I command th--what the fuck."
His arms drop; he staggers, collects himself as one hand goes to worry at his mouth. The rest of his face stays impassive, although his breathing hitches and the arm at his side trembles all the way down to the fingertips. More than the usual 'aaaaaaaa where am I' related shock is simple physical exhaustion, whatever it was he was doing husked him out, left him - well. Left him what, exactly?
"Goddamn," he murmurs, half to himself, half to - none of your damn business, that's who. "I really am getting old." A simple summoning, how do you fuck that up? Unless - he's not thinking about it, patting his pockets restlessly instead, and noticing the bracelet for the first time. "....Jesus."
The pocket search becomes more frantic. "Didn't just botch a summoning then, unless I hit the jewelry district on the way out." His expression flickers but doesn't crack as he finds not exactly what he was looking for in one pocket, but a woefully acceptable alternative. This turns out to be chewing gum, which he pops into his mouth like it's personally offended him.
The alternative he's not voicing is that he's dead, of course - summoning can kill a person, this wouldn't even be the first time. And there's no reason Hell shouldn't have an antechamber; it's been twenty years since he was ....admitted there, if you will. He shakes his shoulders out, fixes his shirt and coat sleeves, then moves to investigate the tablet, circling it like it might spring, but not picking it up yet. "At least the decor is nice. Very proto-scifi, I like it."
John Constantine: nerd. --just kidding. But nerd is still preferable to dead, frankly.