[Egon doesn't actually catch the first part of the stranger's video post--though he does catch the murder joke. He remains mildly interested in the video, as ghosts of any sort are always of interest to him. When the person gets jumped, he blinks, peering closer in concern.

He doesn't recognize him as Winston--why would he? The Winston in his dimension looks different, older. More like Ernie Hudson.]

Are you alright? [His flat tone makes him sound utterly unconcerned.] You know, it's unwise to go into notably haunted areas without proper equipment and preparation beforehand.

[As if the Ghostbusters ever spend more than five minutes "preparing" for any bust.]