Okay, so I guess this would go after maybe Justice League: Part 2 maybe? Or maybe after a Suicide Squad sequel. Either way it would have to be after the Justice League are household names in the DCEU. I know it's longer than the average after-credit scene, but I hope you enjoy!
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Camera's point of view is sitting on Amanda Waller's desk, the room is mostly dark, and the desk is only lit by a desklamp. Only thing visible is the middle of the desk, which shows several scattered manila folders and a document on top of them that she is writing on with black pen.
The camera angle doesn't change but you hear the office door open, and light shine in briefly.
"Come in," she says sternly. Camera angle still unchanged. The figure comes in, shuts the door. It's dark again, and the figure of the outline is visible as he sits in the chair opposite Waller's desk.
Chris Pine's voice says out of the darkness. It's Steve Trevor, his face barely lit by the desk lamp. "It was urgent...?"
"No, but I didn't want to wait." Camera angle still unchanged, her hands stack the manila folders and hands them to Trevor. "I understand your schedule is cleared up...you have a new assignment, Colonel."
Trevor leans forward, his face more visible now, as he opens the top file, and reads, hesitantly and skeptically, "Justice League of ... of America?" He asks, flipping through the various files. "But...but why?" Camera angle changes to Trevor's perspective, and Waller's face, now, is dimly lit and she looks excessively pissed. Camera angle changes back and forth during the following dialogue:
"Because the 'Justice League' is a power group of essential gods. We have zero control over them, and there is no guarentee of any loyalty to us. This country needs their own source of security."
"The Justice League already is their sense of security."
"Trevor, open your eyes. Those people out there are scared and--"
"Maybe they'd already feel safer if you weren't busy making 'super-villain' black ops units..." Trevor says smugly. Waller's face is shown, and she is unamused. Silence for a few seconds. "They tell me more than you think..." He opens a few files. "And do you...do you really wanna do this? You have a--"
"It is not an option, Trevor."
"These people are better fit for your 'death squad'. These are not the shining beacon of America." Trevor said, annoyed and increasingly angered. Waller is silent. "I mean look," he says, quickly shuffling through the files, "you got Queen? A cat burglar? A damn Green Lantern?...And I haven't even heard of most of the rest," Trevor says, as he leans back in his chair, closer into the darkness, and it is faintly visible that he is rubbing the area of his head above his eyebrows.
"Trevor. It. Is. Not an option."
"Amanda, you realize this stupid as hell--"
"Trevor, there is no negotiation...a couple of those are already signed on. We're moving ahead of this...and you are, too." The silence is long and awkward.
After a good bit, Trevor sighs, and angrily, yet collected, lays the files back on the desk. "Fine. Where do we start..?
The camera shows Amanda Waller's dim face. She smirks, coldy, eerily, and leans back in her ergonomic office chair. Behind her, two red eyes very faintly appear, and as they get brighter a neck, torso, and arms very dimly appear, too. The Martian Manhunter.
Fade to Black.