What's the meaning of the last part of Hadith Al-Musnad 26/230?

Question

In Saheeh Ibn Hibbaan and Musnad Ahmad (26/230):

أن نبي الله صلى الله عليه وسلم قال: أربعة يوم القيامة: رجل أصم لا يسمع شيئا، ورجل أحمق، ورجل هرم، ورجل مات في فترة، فأما الأصم فيقول: رب، لقد جاء الإسلام وما أسمع شيئا، وأما الأحمق فيقول: رب، لقد جاء الإسلام والصبيان يحذفوني بالبعر، وأما الهرم فيقول: رب، لقد جاء الإسلام وما أعقل شيئا، وأما الذي مات في الفترة فيقول: رب، ما أتاني لك رسول، فيأخذ مواثيقهم ليطيعنه، فيرسل إليهم أن ادخلوا النار، قال: فوالذي نفس محمد بيده، لو دخلوها لكانت عليهم بردا وسلاما

the Prophet of Allaah SAWS (peace and blessings of Allaah be upon him) said: There are four (who will protest) to Allaah on the Day of Resurrection: the deaf man who never heard anything, the insane man, the very old man, and the man who died during the fatrah (the interval between the time of Eesaa (Jesus, upon whom be peace) and the time of Muhammad SAWS (peace and blessings of Allaah be upon him)). The deaf man will say, O Lord, Islam came but I never heard anything. The insane man will say, O Lord, Islam came but the children ran after me and threw stones at me. The very old man will say, O Lord, Islam came but I did not understand anything. The man who died during the fatrah will say, O Lord, no Messenger from You came to me. He will accept their promises of obedience, then word will be sent to them to enter the Fire. By the One in Whose hand is the soul of Muhammad, if they enter it, it will be cool and safe for them.

Particularly, in this part:

فوالذي نفس محمد بيده، لو دخلوها لكانت عليهم بردا وسلاما

By the One in Whose hand is the soul of Muhammad, if they enter it, it will be cool and safe for them.

What does this mean? Does it mean they will be in Jahannum, but the fire will feel cold and that they won't see Jannah?

Jazakum Allah khayran

Answer 1

The last part of the hadith is not referring to Jahannam even if the wording of the hadith may lead to this conclusion. But to explain this we need to go deeper:

This hadith is used as an evidence by those scholars who say that the people of al-Fatrah and similar people will be tested and judged on the day of judgment. In fact a version of this narration actually says that some of those people will enter Jannah while others will enter Jahannam,
The other scholars hold the opinion that they will enter Janah directly based on:

... And never would We punish until We sent a messenger. (17:15)

So the last statement of the hadith refers to those of them who will enter Jannah.