I didn't know the technical term gemination for っ, appreciate it. Can't it manifest somewhat similarly to stops/plosives though? English doesn't generally use those followed by the same consonant within the same word, but the phrase "port ten" is almost like the t consonant in itte, but with less of a pause in the middle. Contrast it with the word "portend" and you can see that we have a little bit more of a pause in "port ten".