Is performing ablution upon hearing the Iqamah, as mentioned in the Hadith "The Adhan during the time of the Messenger of Allah was twice… when we heard the Iqamah, we would perform ablution, then go out to prayer," considered laziness concerning prayer due to potentially missing the opening Takbir and perhaps other actions of the prayer?

The authenticity of Ibn 'Umar's statement, "When we heard the Iqamah, we would perform ablution and then go out to prayer," is found in sound narrations. It is possible that this occurred for some Companions sometimes due to an excuse or a delay, but they would still catch the prayer with the Imam because the Prophet, peace and blessings be upon him, would prolong the first rak'ah. It is also possible that this was an action of Ibn 'Umar before he reached maturity, as he was a young boy and his house was close to the mosque. This action indicates permissibility, not preference, provided one catches the prayer with the Imam, and it does not contradict the virtue of hastening and arriving early for prayer.