We are working under the assumption that it is worthwhile to continue davening at your minyan. (This may depend on more factors, including subjective ones, than we can address in this forum.)
The simplest option is to daven faster. The Yaskil Avdi[1] suggests speeding up at the end of Shemoneh Esrei (within reason, of course) if doing so will enable one to finish in time for Kedusha. However, almost all poskim reason that one’s kavana is so critical to his tefilla that he should not tamper with it even to facilitate saying Kedusha.
It is essential to evaluate the importance of taking part in saying Kedusha. The gemara[2] writes that one who comes to shul late and will be unable to finish Shemoneh Esrei in time for Kedusha should delay starting Shemoneh Esrei. This implies that Kedusha is more important than tefilla b’tzibbur.[3] On the other hand, the consensus of poskim rules that one who is ready to start Shemoneh Esrei with everyone else, but davens slowly, should start normally, even at the expense of missing Kedusha. The different explanations of how to reconcile the apparent contradiction between this ruling and the gemara’s instruction impact our case.
The Pri Megadim[4] suggests that if one starts Shemoneh Esrei after the tzibbur[5] has begun, he does not get the full effect of tefilla b’tzibbur. Based on this, we can argue that in truth, tefilla b’tzibbur is more important than answering to Kedusha, but the gemara[6] instructs one not to start Shemoneh Esrei because Kedusha has precedence over a partial tefilla b’tzibbur.[7] Accordingly, if one is ready to begin Shemoneh Esrei with the tzibbur, he should do so even if that means that he will not be able to answer to Kedusha.
The Bi’ur Halacha[8] raises an additional possibility. When one is ready to begin Shemoneh Esrei along with the tzibbur, he is faced with the immediate obligation of tefilla b’tzibbur, whereas the obligation of Kedusha arises only in the future. In general, we do not push off doing mitzvot in the present just because it may interfere with doing other mitzvot in the future.[9]
The Az Nidberu[10] offers a third possibility. Only when one is late for Shemoneh Esrei as a result of negligence do we require him to wait due to the prospect of missing Kedusha. In contrast, if he will not finish Shemoneh Esrei on time for Kedusha because he davens slowly, we let him start Shemoneh Esrei nonetheless.
A fourth distinction is that if on occasion one starts Shemoneh Esrei late, he must sacrifice his tefilla b’tzibbur to be ready to answer Kedusha. However, one who davens slower than his counterparts should not be deprived of tefilla b’tzibbur on an ongoing basis.[11]
All the above agree that one who is ready to start Shemoneh Esrei with the tzibbur does so without taking Kedusha into account. However, there are other situations that depend on which explanations one accepts. What does one do if he regularly is not ready to begin Shemoneh Esrei with his fellow congregants because the recitation of Kri’at Shema and its berachot take him longer? According to the first two reasons above, he should wait at least until chazarat hashatz to start Shemoneh Esrei,[12] since anyway he will not receive the full benefit of tefilla b’tzibbur and he must be concerned about the upcoming Kedusha. However, according to the third and fourth approaches, he can start Shemoneh Esrei when he is ready and listen quietly to Kedusha at the appropriate point.[13] He is not at fault for starting late, and if he were compelled to wait, he would regularly miss out on tefilla b’tzibbur.
All things considered, however, it is best to avoid starting late, since then one misses out on a full tefilla b’tzibbur according to some opinions and/or on responding during Kedusha.
One possible way for a slow davener to finish Shemoneh Esrei in time for Kedusha is to start Shemoneh Esrei before the congregation. Is this a good option? The gemara[14] cautions against beginning one’s tefilla before the congregation. On the other hand, we rule that it is permitted to do so if the tzibbur will miss the deadline for tefilla.[15] What is the problem with going ahead? It might be because one thereby misses tefilla b’tzibbur.[16] If so, we would have to determine to what extent there is a problem when one misses saying the critical first part of Shemoneh Esrei with the tzibbur but finishes with the tzibbur, and whether being in a position to recite Kedusha is sufficient justification.
Many poskim write that there is an issue of disrespect to the tzibbur when one begins Shemoneh Esrei before them.[17] According to this approach, we would have to determine whether people will be understanding in light of the motivation of enabling one to recite Kedusha, and, if not, whether the need justifies any subsequent fallout. Some poskim allow going ahead of the tzibbur,[18] but we feel that the negative usually outweighs the positive.
One option for the slow davener is to come early to shul and begin the berachot of Kri’at Shema when the congregation is reciting P’sukei D’Zimra. That way, he can proceed at his natural pace and start Shemoneh Esrei with the tzibbur. During Birchot Kri’at Shema, he should answer Amen Y’hei Shmei… and the last Amen of Kaddish and respond to Barchu.[19]