We do not know of any basis for what is mentioned in the question, that when the Prophet (blessings and peace of Allah be upon him) returned from his Mi`raj he found his bedsheet still warm, and he found a vessel that had been overturned before his `Mi`raj still dripping water, and he found the chain of the door still swinging. It is not permissible to narrate such stories, because of what they involve of tedious exaggeration.
We do not know of anyone who says that the bed of the Messenger of Allah (blessings and peace of Allah be upon him) had a bedsheet (Mala’ah); using the word Mala’ah (bedsheet) in reference to the cover of a bed is a modern usage; the Arabic word Mala’ah originally refers to an enveloping garment (Milhafah) or waist wrapper (izar). (See Lisan Al-`Arab (1/160) and An-Nihayah (4/352)
Shaykh Ash-Shuqayri (may Allah have mercy on him) said:
“The idea that the Prophet (blessings and peace of Allah be upon him) went and came back during the night of the Isra’ (Night Journey) and his bed had not grown cold is not proven; rather it is one of the lies that are told by people.” (As-Sunan wal Mubtada`at, 143)
Similarly, it is not known that the door of the Prophet (blessings and peace of Allah be upon him) had a chain with which it was locked. In the beginning, most of the houses did not have doors. `Abd Ar-Rahman ibn Zayd said concerning the verse (interpretation of the meaning), “There is no restriction… nor on yourselves, if you eat from your houses… or (from the house) of a friend” [An-Nur 24:61]: Rather this was the case in the beginning, as they did not have doors, and curtains were used instead. (Tafsir At-Tabari (19/221)
Another indication that this notion is false is the report narrated by Al-Bukhari (3342) and Muslim (163) from Anas ibn Malik, who said: Abu Dharr used to narrate that the Messenger of Allah (blessings and peace of Allah be upon him) said: “The roof of my house was opened when I was in Makkah, and Jibril (peace be upon him) came down and split open my chest, then he washed it with Zamzam water. Then he brought a golden basin filled with wisdom and faith and emptied it into my chest. Then he sealed it and took my hand, and took me up to heaven…. This indicates that the Prophet (blessings and peace of Allah be upon him) was taken directly up to heaven, via an opening in the roof, not via the door.
And Allah knows best.