I daven Maariv in a shul where there is a Chiyuv (an ‘obliged’ person in mourning who leads the prayers) and he davens very fast. I can not keep up with him at the end of the Krias Shema brochos and I’m still saying Hashkivenu, when he is already about to end the last bracha that many omit (Nusach Ashkenaz) of ‘Baruch Hashem Leolam.” Can I just skip that last bracha?

Horav Horav Shlomo Miller’s Shlit’a opinion is that it could be omitted in that case. On a similar question (2158) regarding someone who Davens Maariv in a minyan that is too fast, and he can’t say the complete “Baruch Hashem Leolam” before beginning the amida betzibur, if he should he omit some or all of the psukim and just continue with the bracha of Yiru Einenu at the end, or if should he omit the complete addition that in other nuschaot is also excluded. we wrote: “Horav Shlomo Miller’s Shlit’a opinion is that the added section of “Baruch Hashem Leolam” before beginning the amida, has to be said complete or not at all. If one will not be able to begin the amida together with the tzibur, it should be totally omitted.” However on question 2438 what happens if someone is davening and already started saying that bracha, but then the chazan rushed and he finished it while he was still in the middle of the bracha. Should he stop right there and begin the amida with everybody or finish the bracha and maybe lose Tefilah Betzibur, we wrote: “Horav Shlomo Miller’s Shlit’a opinion is that indeed, if someone realizes on the onset that he will not be able to recite the complete brocho of “Baruch Hashem Leolam” before beginning the amida of Maariv, he should better avoid it. However, if he already started saying it, and then realizes he won’t be able to finish it on time to begin the amida together with the Tzibur, he should skip and just say the end brocho of “Yiru Einenu”. Horav Horav Shlomo Miller’s Shlit’a opinion is similar.