If one is lagging behind the tzibbur and did not start שמו״ע with them, they may not start if they will miss קדושה.
Thanks for bringing this up. This is a very important Halacha which unfortunately is not very well known. Applies even more when people come late to Mincha.
One heter I have seen over the years is if this individual is someone who always davens a long shmoneh esrai and he never makes kedusha in time, he may be allowed to start even though he will not finish in time.
Btw, does not only apply to kedusha. Applies to הקל הקדוש, שומע תפלה, מודים, וקדיש.