The guard watched suspiciously, as I placed my hand on the Ident scanner and gazed into its glass-eye. Lights flickered from amber to green and pinged confirmation of my identity. I could see his suspicion grow as he glanced repeatedly from the screen to me. His finger hovered over the panic button ready to lock down the lobby. I smiled knowing he did not trust his eyes but the scanner did not lie.
“Dr. Narita?” He said, finger still poised over the button.
“Gave you a shock, did I?” I choke backed a laugh not wanting to be rude. “Yes, it’s me Keigo, but I think I’ll need a new picture ID on Monday.” I said as calmly as possible.
He stood and leaned across the counter staring into my eyes. “It is you Dr. Narita,” he still didn’t look convinced

I think the hook for me is wondering why the guy's face is different. I also think you could have gotten to the hook faster. It isn't terrible or even bad, but it's buried as it is. Punch me in the face with it. The guard's suspicious gaze confirmed the need for a new ID or whatever.

However:

You have cheated a little in the first paragraph (creating false tension) by having the viewpoint character not use the guard's name - Keigo. If the viewpoint character knows who the guard is, then his name should be used and include that he was wearing his uniform and standing (or sitting) guard as usual. I assume he is sitting since he stands in last paragraph, although this isn't clear.

You are also telling and not showing. In doing so, you are using filters - "I could see", "knowing", "look". The use of these is not necessarily wrong, but they should be used as sparingly as possible. Consider what made Keigo appear suspicious. Did he furrow his eyebrows or raise one inquisitively? Instead of telling us that his suspicion was growing, all you really need is "He glanced repeatedly from the screen to me." Instead of adding 'he still didn't look convinced', simply add question mark at end of "It is you...(?)"

There are some minor grammar and punctuation details to consider:
- no comma is needed in the first sentence.
- you should use a comma in the last sentence of first paragraph after 'eyes' because it is a compound sentence and you are changing direction. If the second part of the sentence continued the thought of the first part, then the comma would not be necessary.
- "Dr. Narita?" he said, finger... (the 'he' should be lower-case)
- 'I choked back..." instead of 'choke backed'
- "Yes, it’s me, Keigo, but I..." - I know it seems like a lot of commas, but you need one before and after 'Keigo'. You may want to consider rewording to avoid excessive commas.
- "Yes,...ID on Monday," I said... (need comma after 'Monday', not period - rules of grammar regarding attributions following quotation marks - question and exclamation marks are OK, not periods).

I also noticed that you used three adverbs. This isn't too bothersome for me, but you might want to consider if they are needed. They become more noticeable following the word 'said' as in last paragraph - this also drifts into "telling" areas.

I would continue reading as it now stands, but with trepidation.

Revised 13

Keigo watches me suspiciously from behind the desk as I place my hand on the scanner and gaze into it’s glass eye. Lights flicker from amber to green and it pings confirmation of my identity. He tilts his head to the side and squints as he glances repeatedly from the screen to me. His finger hovers over the panic button ready to lock down the lobby. I smile knowing he doesn’t trust his eyes, but the scanner does not lie.
“Dr. Narita?” he said, standing and leaning across the counter staring into my eyes. “It is you Dr. Narita? But why . . .?” He blurts out, disgust bright as a neon shown on his face. He quickly averts his eyes, trying to regain self-control before continuing in a more contrite tone. “Excuse me Dr. Narita it is none of my concern, forgive me, but you will need a new picture ID.”

You need to find one verb tense and stick with it - you are going back and forth between present and past. In present, 'said' will be 'says'; however, my personal opinion is that past works better - this is only a matter of taste, but I believe past is also easier to write.

You also address "Dr. Narita" by name three times in this second paragraph. If you address someone by name admidst other dialogue in the same sentence, then you should separate the name with commas like so: "It is you, Dr. Narita?" or "Excuse me, Dr. Narita, it is..." I'm not sure about the level of familiarity, but you might consider using the MC's first name in Keigo's second address.

There are a few more minor grammar/punctuation problems similar to what I pointed out in my first response - "But why...?" he (lower case) blurts... and 'shown' should be 'shows' or 'showed' depending on which tense you choose.