Dr. Anwar Sahib makes it clear that once the Hadd is ordered, there is no concession in it.

However, on one occasion the Prophet (ﷺ) said to the Sahaba [who were executing punishment of stoning on Maiz (رضى الله عنه)], "Why did you not leave him, for he might repent and Allah would accept his repentance".

Can you please explain the statement?

If a punishment like stoning is being carried out and a person manages to escape, according to the Shariah, we are not supposed to run after him/her to finish him off. So, the statement of the Prophet (ﷺ) is used as an evidence to support the above and it is not understood as a concession. [1]

Reference:

[1] Sheikh S Al-Fawzaan, A Summary of Islamic Jurisprudence, 2/598